scsi: arcmsr: Stop __builtin_strncpy complaining about a lack of space for NUL

SCSI strings like inqdata are not NUL terminated.

Fixes the following W=1 kernel build warning(s):

 In file included from include/linux/bitmap.h:9,
 from include/linux/nodemask.h:95,
 from include/linux/mmzone.h:17,
 from include/linux/gfp.h:6,
 from include/linux/umh.h:4,
 from include/linux/kmod.h:9,
 from include/linux/module.h:16,
 from drivers/scsi/arcmsr/arcmsr_hba.c:47:
 In function ‘strncpy’,
 inlined from ‘arcmsr_handle_virtual_command’ at drivers/scsi/arcmsr/arcmsr_hba.c:3055:3:
 include/linux/string.h:297:30: warning: ‘__builtin_strncpy’ output truncated before terminating nul copying 4 bytes from a string of the same length [-Wstringop-truncation]
 297 | #define __underlying_strncpy __builtin_strncpy
 | ^
 include/linux/string.h:307:9: note: in expansion of macro ‘__underlying_strncpy’
 307 | return __underlying_strncpy(p, q, size);
 | ^~~~~~~~~~~~~~~~~~~~
 In function ‘strncpy’,
 inlined from ‘arcmsr_handle_virtual_command’ at drivers/scsi/arcmsr/arcmsr_hba.c:3053:3:
 include/linux/string.h:297:30: warning: ‘__builtin_strncpy’ output truncated before terminating nul copying 16 bytes from a string of the same length [-Wstringop-truncation]
 297 | #define __underlying_strncpy __builtin_strncpy
 | ^
 include/linux/string.h:307:9: note: in expansion of macro ‘__underlying_strncpy’
 307 | return __underlying_strncpy(p, q, size);
 | ^~~~~~~~~~~~~~~~~~~~
 In function ‘strncpy’,
 inlined from ‘arcmsr_handle_virtual_command’ at drivers/scsi/arcmsr/arcmsr_hba.c:3051:3:
 include/linux/string.h:297:30: warning: ‘__builtin_strncpy’ output truncated before terminating nul copying 8 bytes from a string of the same length [-Wstringop-truncation]
 297 | #define __underlying_strncpy __builtin_strncpy
 | ^
 include/linux/string.h:307:9: note: in expansion of macro ‘__underlying_strncpy’
 307 | return __underlying_strncpy(p, q, size);
 | ^~~~~~~~~~~~~~~~~~~~

Link: https://lore.kernel.org/r/20201102102544.1018706-1-lee.jones@linaro.org
Cc: support@areca.com.tw
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/arcmsr/arcmsr_hba.c

@@ -3201,11 +3201,11 @@ static void arcmsr_handle_virtual_command(struct AdapterControlBlock *acb,
 		/* ISO, ECMA, & ANSI versions */
 		inqdata[4] = 31;
 		/* length of additional data */
-		strncpy(&inqdata[8], "Areca   ", 8);
+		memcpy(&inqdata[8], "Areca   ", 8);
 		/* Vendor Identification */
-		strncpy(&inqdata[16], "RAID controller ", 16);
+		memcpy(&inqdata[16], "RAID controller ", 16);
 		/* Product Identification */
-		strncpy(&inqdata[32], "R001", 4); /* Product Revision */
+		memcpy(&inqdata[32], "R001", 4); /* Product Revision */
 
 		sg = scsi_sglist(cmd);
 		buffer = kmap_atomic(sg_page(sg)) + sg->offset;