fix the following 'make includecheck' warning:

  arch/arm/mach-omap1/mcbsp.c: mach/irqs.h is included more than once.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: Eduardo Valentin <eduardo.valentin@nokia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>