lib/crc: remove unnecessary prompt for CONFIG_CRC32 and drop 'default y'

All modules that need CONFIG_CRC32 already select it, so there is no
need to bother users about the option, nor to default it to y.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250401221600.24878-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

lib/Kconfig

@@ -177,14 +177,8 @@ config CRC_ITU_T
 	  functions require M here.
 
 config CRC32
-	tristate "CRC32/CRC32c functions"
-	default y
+	tristate
 	select BITREVERSE
-	help
-	  This option is provided for the case where no in-kernel-tree
-	  modules require CRC32/CRC32c functions, but a module built outside
-	  the kernel tree does. Such modules that use library CRC32/CRC32c
-	  functions require M here.
 
 config ARCH_HAS_CRC32
 	bool