kmemleak uses crc32 functions so it needs to select CRC32.
Fixes build error:

kmemleak.c:(.text+0x7ce62): undefined reference to `crc32_le'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>