[CIFS] add extra null attr check
[CIFS] add extra null attr check

Although attr == NULL can not happen, this makes cifs_set_file_info safer
in the future since it may not be obvious that the caller can not set
attr to NULL.

Signed-off-by: Steve French <d47560e3bac353b8d509d093b1d727868ac7ddf3@us.ibm.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas