ARM: mxs: rename debug-macro.S for multiplatform build

Rename arch/arm/mach-mxs/include/mach/debug-macro.S to
arch/arm/include/debug/mxs.S for multiplatform build.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

arch/arm/Kconfig.debug

@@ -591,6 +591,7 @@ config DEBUG_LL_INCLUDE
 				 DEBUG_IMX6Q_UART
 	default "debug/highbank.S" if DEBUG_HIGHBANK_UART
 	default "debug/mvebu.S" if DEBUG_MVEBU_UART
+	default "debug/mxs.S" if DEBUG_IMX23_UART || DEBUG_IMX28_UART
 	default "debug/omap2plus.S" if DEBUG_OMAP2PLUS_UART
 	default "debug/picoxcell.S" if DEBUG_PICOXCELL_UART
 	default "debug/socfpga.S" if DEBUG_SOCFPGA_UART