ARC: memset: fix build with L1_CACHE_SHIFT != 6

In case of 'L1_CACHE_SHIFT != 6' we define dummy assembly macroses
PREALLOC_INSTR and PREFETCHW_INSTR without arguments. However
we pass arguments to them in code which cause build errors.
Fix that.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: <stable@vger.kernel.org>    [5.0]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>