ARM: Update mach-types to fix mxs build breakage

Add entry m28evk to fix the following mxs build breakage.

  CHK     include/generated/compile.h
  CC      arch/arm/mach-mxs/clock-mx28.o
arch/arm/mach-mxs/clock-mx28.c: In function 'clk_misc_init':
arch/arm/mach-mxs/clock-mx28.c:748: error: implicit declaration of
function 'machine_is_m28evk'
make[1]: *** [arch/arm/mach-mxs/clock-mx28.o] Error 1
make: *** [arch/arm/mach-mxs] Error 2

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/tools/mach-types

@@ -1123,5 +1123,6 @@ blissc			MACH_BLISSC		BLISSC			3491
 thales_adc		MACH_THALES_ADC		THALES_ADC		3492
 ubisys_p9d_evp		MACH_UBISYS_P9D_EVP	UBISYS_P9D_EVP		3493
 atdgp318		MACH_ATDGP318		ATDGP318		3494
+m28evk			MACH_M28EVK		M28EVK			3613
 smdk4212		MACH_SMDK4212		SMDK4212		3638
 smdk4412		MACH_SMDK4412		SMDK4412		3765