davinci: da8xx: sparse cleanup: remove duplicate entries in irq priorities

This patch helps get rid of the following sparse warnings
of the type:

  CHECK   arch/arm/mach-davinci/da830.c
arch/arm/mach-davinci/da830.c:1026:3: warning: Initializer entry defined twice
arch/arm/mach-davinci/da830.c:1027:3:   also defined here

coming from the irq priorities array init.

Apart from one instance of genuinie repetition, most are are instances
of multiple #defines of the same interrupt number. I have not
removed the multiple definitions from the irq.h file in the hope
that someone might decide to use them as shared interrupts at some
point of time. The priority initialization however needs to be done
only once and hence has been corrected.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>