treewide: remove explicit rules for *offsets.s

These explicit rules are unneeded because scripts/Makefile.build
provides a pattern rule to create %.s from %.c

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/mach-omap2/Makefile

@@ -236,9 +236,6 @@ obj-y					+= omap_phy_internal.o
 
 obj-$(CONFIG_MACH_OMAP2_TUSB6010)	+= usb-tusb6010.o
 
-arch/arm/mach-omap2/pm-asm-offsets.s: arch/arm/mach-omap2/pm-asm-offsets.c
-	$(call if_changed_dep,cc_s_c)
-
 include/generated/ti-pm-asm-offsets.h: arch/arm/mach-omap2/pm-asm-offsets.s FORCE
 	$(call filechk,offsets,__TI_PM_ASM_OFFSETS_H__)