msm: gsi: fix for clearing IEOB interrupt

Clear IEOB interrupt only for channels that have
IEOB interrupt enabled. This is needed to make sure IEOB interrupt
is not missed after switching from polling to interrupt.

CRs-Fixed: 1014388
Change-Id: Ia6484ed03d9508b827f8c7e4dadb84c14e306bd9
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>