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: Ie721a25f38a720af05d2335067aa4ce6870b6055
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>