lib/Kconfig.debug: properly split hash test kernel entries

Split TEST_HASH so that each entry only has one file.

Note that there's no stringhash test file, but actually
<linux/stringhash.h> tests are performed in lib/test_hash.c.

Link: https://lkml.kernel.org/r/20211208183711.390454-5-isabbasso@riseup.netReviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
Cc: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Enzo Ferreira <ferreiraenzoa@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig.debug

@@ -2210,9 +2210,17 @@ config TEST_RHASHTABLE
 config TEST_HASH
 	tristate "Perform selftest on hash functions"
 	help
-	  Enable this option to test the kernel's integer (<linux/hash.h>),
-	  string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
-	  hash functions on boot (or module load).
+	  Enable this option to test the kernel's integer (<linux/hash.h>), and
+	  string (<linux/stringhash.h>) hash functions on boot (or module load).
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config TEST_SIPHASH
+	tristate "Perform selftest on siphash functions"
+	help
+	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
+	  functions on boot (or module load).
 
 	  This is intended to help people writing architecture-specific
 	  optimized versions.  If unsure, say N.

lib/Makefile

@@ -61,7 +61,8 @@ obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
 obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
 CFLAGS_test_bitops.o += -Werror
 obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
-obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o
+obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o
+obj-$(CONFIG_TEST_HASH) += test_hash.o
 obj-$(CONFIG_TEST_IDA) += test_ida.o
 obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o
 CFLAGS_test_kasan.o += -fno-builtin