Add arm64 configuration and device tree differences.

Disable MMC_BCM2835_SDHOST and MMC_BCM2835 since these drivers are crashing at the moment.

ARM64: Modify default config to get raspbian to boot (#1686)

1. Enable emulation of deprecated instructions.
2. Enable ARM 8.1 and 8.2 features which are not detected at runtime.
3. Switch the default governer to powersave.
4. Include the watchdog timer driver in the kernel image rather then a module.

Tested with raspbian-jessie 2016-09-23.

Author: Electron752

arch/arm64/Kconfig.platforms

@@ -1,5 +1,27 @@
 menu "Platform selection"
 
+config MACH_BCM2709
+        bool
+
+config ARCH_BCM2709
+        bool "Broadcom BCM2709 family"
+        select MACH_BCM2709
+        select HAVE_SMP
+        select ARM_AMBA
+        select COMMON_CLK
+        select ARCH_HAS_CPUFREQ
+        select GENERIC_CLOCKEVENTS
+        select MULTI_IRQ_HANDLER
+        select SPARSE_IRQ
+        select MFD_SYSCON
+        select VC4
+        select USE_OF
+        select ARCH_REQUIRE_GPIOLIB
+        select PINCTRL
+        select PINCTRL_BCM2835
+        help
+          This enables support for Broadcom BCM2709 boards.
+
 config ARCH_SUNXI
 	bool "Allwinner sunxi 64-bit SoC Family"
 	select GENERIC_IRQ_CHIP

arch/arm64/boot/dts/broadcom/Makefile

@@ -1,6 +1,7 @@
 dtb-$(CONFIG_ARCH_BCM2835) += bcm2837-rpi-3-b.dtb
 dtb-$(CONFIG_ARCH_BCM_IPROC) += ns2-svk.dtb
 dtb-$(CONFIG_ARCH_VULCAN) += vulcan-eval.dtb
+dtb-$(CONFIG_ARCH_BCM2709) += bcm2710-rpi-3-b.dtb
 
 always		:= $(dtb-y)
 subdir-y	:= $(dts-dirs)

arch/arm64/boot/dts/broadcom/bcm2710-rpi-3-b.dts

@@ -0,0 +1,3 @@
+#define RPI364
+
+#include "../../../../arm/boot/dts/bcm2710-rpi-3-b.dts"