lib: add module support to crc32 tests

Extract the crc32 test code into its own source file, to allow to
compile it either to a loadable module, or builtin into the kernel.

Link: http://lkml.kernel.org/r/1483470276-10517-1-git-send-email-geert@linux-m68k.orgSigned-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig

@@ -103,8 +103,7 @@ config CRC32
 	  functions require M here.
 
 config CRC32_SELFTEST
-	bool "CRC32 perform self test on init"
-	default n
+	tristate "CRC32 perform self test on init"
 	depends on CRC32
 	help
 	  This option enables the CRC32 library functions to perform a

lib/Makefile

@@ -92,6 +92,7 @@ obj-$(CONFIG_CRC16)	+= crc16.o
 obj-$(CONFIG_CRC_T10DIF)+= crc-t10dif.o
 obj-$(CONFIG_CRC_ITU_T)	+= crc-itu-t.o
 obj-$(CONFIG_CRC32)	+= crc32.o
+obj-$(CONFIG_CRC32_SELFTEST)	+= crc32test.o
 obj-$(CONFIG_CRC7)	+= crc7.o
 obj-$(CONFIG_LIBCRC32C)	+= libcrc32c.o
 obj-$(CONFIG_CRC8)	+= crc8.o