qseecom: use wait_event_interruptible

Kernel threads are not freezable by default, change to use
wait_event_interruptible to prevent a frozen qseecom thread
being blocked until another frozen thread is thawed.

Change-Id: I09d374c763a316201e790d9003b0b9785debd44a
Signed-off-by: Zhen Kong <zkong@codeaurora.org>