staging: lustre: llite: Remove unnecessary test in if condition

Remove unnecessary test on `rc` variable since it has already been
tested previously.
Fixes following smatch warning:
drivers/staging/lustre/lustre/llite/llite_lib.c:1331 ll_setattr_raw()
warn: we tested 'rc' before and it was 'false'

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>