mailbox: cix: Add IRQF_NO_SUSPEND to mailbox interrupt

mailbox: cix: Add IRQF_NO_SUSPEND to mailbox interrupt

During the system suspend process, device interrupts are masked in the
noirq phase. However, SCMI often needs to exchange final messages with the
firmware to complete the power-down transition. Without the IRQF_NO_SUSPEND
flag, the mailbox ISR cannot run during this late stage, leading to SCMI
communication timeouts and error messages like "SCMI protocol wait for
resp timeout" during suspend.

Add the IRQF_NO_SUSPEND flag to the interrupt request to ensure the mailbox
can continue to handle responses during the noirq stages of suspend and
resume, thereby ensuring a reliable power state transition.

Signed-off-by: Dylan Wu <fredwudi0305@gmail.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>