ARM: OMAP: Fix missing makefile options

Although audio and dsp drivers are not integrated yet,
allow compiling in mailbox and mcbsp to see any build
warnings.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/Makefile

@@ -14,9 +14,14 @@ obj-$(CONFIG_OMAP_32K_TIMER)	+= timer32k.o
 # OCPI interconnect support for 1710, 1610 and 5912
 obj-$(CONFIG_ARCH_OMAP16XX) += ocpi.o
 
+obj-$(CONFIG_OMAP_MCBSP) += mcbsp.o
 
 obj-$(CONFIG_CPU_FREQ) += cpu-omap.o
 obj-$(CONFIG_OMAP_DM_TIMER) += dmtimer.o
 obj-$(CONFIG_OMAP_DEBUG_DEVICES) += debug-devices.o
 obj-$(CONFIG_OMAP_DEBUG_LEDS) += debug-leds.o
 obj-$(CONFIG_I2C_OMAP) += i2c.o
+
+# OMAP mailbox framework
+obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
+