soc: qcom: qsee_ipc_irq: Fix irq mapping logic

The hw irq number should be determined by using the bank index and
bit offset of the irq status register. Add a macro to quickly get
the hw irq number from this information.

Change-Id: Ic5e3a193a2b0d145c8d4a593fbff5208a10b099a
Signed-off-by: Chris Lew <clew@codeaurora.org>