slimbus: ngd: remove unnecessary check

SLIM_MSG_CLK_PAUSE_SEQ_FLG is never set in any of the slim core,
so performing a check in ngd driver is totally unnecessary.

Also this patch fixes warning about mc field overflow reported
with CoverityScan.

Making clk pause feature optional will be added to slim core in
next development cycle.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: 917809e2 ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>