OMAP: Tweak omap-common/Makefile since reset.S -> reset.c

Git commit d417d1db5f9092d125ddea882ced77eaa5f3d236 replaced the
omap-common file reset.S with reset.c, but the Makefile was not
adjusted for that.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
diff --git a/arch/arm/cpu/armv7/omap-common/Makefile b/arch/arm/cpu/armv7/omap-common/Makefile
index 1f2fa02..0efc80d 100644
--- a/arch/arm/cpu/armv7/omap-common/Makefile
+++ b/arch/arm/cpu/armv7/omap-common/Makefile
@@ -25,9 +25,8 @@
 
 LIB	= $(obj)libomap-common.o
 
-SOBJS	:= reset.o
-
-COBJS	:= timer.o
+COBJS	:= reset.o
+COBJS	+= timer.o
 COBJS	+= utils.o
 
 ifneq ($(CONFIG_OMAP44XX)$(CONFIG_OMAP54XX),)