cifsd: remove unnecessary parentheses around

Fix warnings from checkpatch.pl --strict :

 CHECK: Unnecessary parentheses around 'brk_op->o_lease->new_state ==
 SMB2_LEASE_NONE_LE'
 #1511: FILE: oplock.c:1511:
 +               if (brk_op->is_lease &&
 +                   (brk_op->o_lease->new_state == SMB2_LEASE_NONE_LE)
 &&
 +                   atomic_read(&brk_op->breaking_cnt))

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>