pinctrl: qcom: Use irq_create_mapping for direct connected GPIOs

On MSM platforms certain GPIOs pins are directly connected to SPI of
GIC parent controller which was using static mapping already present to
get virtual irq number and map it to SPI of GIC.

However with Commit '813aa7765fb4a ("gpiolib: allow gpio irqchip to map
irqs dynamically")' virtual irq number will no more present if the client
drivers have not started using gpio interrupts.

Use irq_create_mapping instead of irq_find_mapping to create mapping for
direct connected GPIOs.

Change-Id: I7bb7616778cb6a071f90d9061f127c88e116e9fd
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>