ARM: dts: msm: Use macro definitions for interrupts for SMP2P

There are some preprocessor macros that represent the supported values
for the `interrupts' property.  Currently we're just hard-coding the
numerical values, which is hard to understand.  Fix this by using the
macros.

Change-Id: I835ac805a4cdc619eab354197faa3bfcc98bd02f
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>