msm: smp2p_gpio: Directly manage irq allocation and mapping

Smp2p_gpio expects to obtain a contiguous set of virtual irq identifiers
to map to the bits of an smp2p entry as virtual gpio lines but does not
require a specific set of irq numbers - any sufficently large set of
contiguous virtual irq identifiers will do.  None of the irq allocate and
map helper functions meet this usecase.  As a result, smp2p_gpio is
required to manage its own allocation and mapping of irqs to gpios.

Directly manage irq allocation and mapping using the raw allocate and map
API instead of incorrectly using the helper functions.

Change-Id: I7ed092af74c393dd00aee81b3fc770c0365d8413
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>