serial: msm_geni_serial: Move the request IRQ call to after resource voting

Sometimes the ISR is called as soon as the driver requests it before the
core is setup and before resource voting is done.
As a defensive check move the request irq to after the core setup and
resource voting is done. Also initialize the runtime status of the device
to suspended before calling the runtime framework to enable runtime power
management.

Change-Id: If234847a41abbb86a47fefd43739a4d9132b477e
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>