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/configs/bcmrpi3_defconfig

@@ -27,19 +27,23 @@ CONFIG_ARM64_VA_BITS=39
 CONFIG_SCHED_MC=y
 CONFIG_NR_CPUS=4
 CONFIG_HOTPLUG_CPU=y
+CONFIG_ARMV8_DEPRECATED=y
+CONFIG_SWP_EMULATION=y
+CONFIG_CP15_BARRIER_EMULATION=y
+CONFIG_SETEND_EMULATION=y
 
 #
 # ARMv8.1 architectural features
 #
-CONFIG_ARM64_HW_AFDBM=n
-CONFIG_ARM64_PAN=n
-CONFIG_ARM64_LSE_ATOMICS=n
-CONFIG_ARM64_VHE=n
+CONFIG_ARM64_HW_AFDBM=y
+CONFIG_ARM64_PAN=y
+CONFIG_ARM64_LSE_ATOMICS=y
+CONFIG_ARM64_VHE=y
 
 #
 # ARMv8.2 architectural features
 #
-CONFIG_ARM64_UAO=n
+CONFIG_ARM64_UAO=y
 CONFIG_ARM64_MODULE_CMODEL_LARGE=n
 CONFIG_RANDOMIZE_BASE=n
 
@@ -98,7 +102,7 @@ CONFIG_ZBOOT_ROM_TEXT=0x0
 CONFIG_ZBOOT_ROM_BSS=0x0
 CONFIG_CMDLINE="console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait"
 CONFIG_CPU_FREQ=y
-CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
+CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE=y
 CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
 CONFIG_CPU_FREQ_GOV_USERSPACE=y
 CONFIG_CPU_FREQ_GOV_ONDEMAND=y
@@ -687,7 +691,7 @@ CONFIG_SENSORS_SHTC1=m
 CONFIG_THERMAL=y
 CONFIG_THERMAL_BCM2835=y
 CONFIG_WATCHDOG=y
-CONFIG_BCM2835_WDT=m
+CONFIG_BCM2835_WDT=y
 CONFIG_UCB1400_CORE=m
 CONFIG_MFD_STMPE=y
 CONFIG_STMPE_SPI=y