ARM: dts: msm: Update MPM interrupt mapping for USB

The USB HS PHY's D+ and D- high voltage interrupts are
routed to MPM pins 48 and 49, respectively. Update the
MPM-GIC mapping as both of these are handled by the
USB 3.0 controller interrupt.

Change-Id: I87ae4153d766ce68d10a83babaf170facb6205ce
Signed-off-by: Jack Pham <jackp@codeaurora.org>