Fix out-of-bound memory write in int4 kernels

* Fix condition for left-over rows store.

Resolves: COMPMID-7245
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>

Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Approved-by: Felix Johnny Thomasmathibalan <felixjohnny.thomasmathibalan@arm.com>