[CIFS] fs/cifs/Kconfig: CIFS depends on CRYPTO_HMAC

linux-2.6.37-rc1: I compiled a kernel with CIFS which subsequently
failed with an error indicating it couldn't initialize crypto module
"hmacmd5".  CONFIG_CRYPTO_HMAC=y fixed the problem.

This patch makes CIFS depend on CRYPTO_HMAC in kconfig.

Signed-off-by: Jody <Bruchon&lt;jody@nctritech.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>