soc: qcom: qsee_ipc_irq: Change to level trigger irq

Change the expected irq handling to level interrupts and add the
IRQF_ONESHOT flag to perform proper mask handling. Move the irq clear
before the work to prevent missing the level trigger interrupt.

Change-Id: I290f1534601f4aa625c9a8f5c564019e4eaf5359
Signed-off-by: Chris Lew <clew@codeaurora.org>