x86, boot: Use .code16 instead of .code16gcc

This reverts commit 28b48688 ("x86, boot: use .code16gcc instead
of .code16").

Versions of binutils older than 2.16 are already not working, so this
workaround is no longer necessary either.  At the same time, some of
the transformations that .code16gcc does can be *extremely*
counterintuitive to a human programmer.

[ hpa: folded ret -> retl and call -> calll fixes from followup patch ]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1388788242.2391.75.camel@shinybook.infradead.orgSigned-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/boot/bioscall.S

@@ -13,7 +13,7 @@
  * touching registers they shouldn't be.
  */
 
-	.code16gcc
+	.code16
 	.text
 	.globl	intcall
 	.type	intcall, @function

arch/x86/boot/copy.S

@@ -14,7 +14,7 @@
  * Memory copy routines
  */
 
-	.code16gcc
+	.code16
 	.text
 
 GLOBAL(memcpy)
@@ -30,7 +30,7 @@ GLOBAL(memcpy)
 	rep; movsb
 	popw	%di
 	popw	%si
-	ret
+	retl
 ENDPROC(memcpy)
 
 GLOBAL(memset)
@@ -45,25 +45,25 @@ GLOBAL(memset)
 	andw	$3, %cx
 	rep; stosb
 	popw	%di
-	ret
+	retl
 ENDPROC(memset)
 
 GLOBAL(copy_from_fs)
 	pushw	%ds
 	pushw	%fs
 	popw	%ds
-	call	memcpy
+	calll	memcpy
 	popw	%ds
-	ret
+	retl
 ENDPROC(copy_from_fs)
 
 GLOBAL(copy_to_fs)
 	pushw	%es
 	pushw	%fs
 	popw	%es
-	call	memcpy
+	calll	memcpy
 	popw	%es
-	ret
+	retl
 ENDPROC(copy_to_fs)
 
 #if 0 /* Not currently used, but can be enabled as needed */
@@ -71,17 +71,17 @@ GLOBAL(copy_from_gs)
 	pushw	%ds
 	pushw	%gs
 	popw	%ds
-	call	memcpy
+	calll	memcpy
 	popw	%ds
-	ret
+	retl
 ENDPROC(copy_from_gs)
 
 GLOBAL(copy_to_gs)
 	pushw	%es
 	pushw	%gs
 	popw	%es
-	call	memcpy
+	calll	memcpy
 	popw	%es
-	ret
+	retl
 ENDPROC(copy_to_gs)
 #endif