armvirt: 32: refresh kernel config

armvirt: 32: refresh kernel config

The diff was genereated by running the following command without
actually changing any kernel config options

	make kernel_menuconfig CONFIG_TARGET=subtarget

Here are some initial findings on the change

 - CONFIG_ARCH_OPTIONAL_KERNEL_RWX is now arch default
 - CONFIG_ARM_GIC_V3_ITS is selected by CONFIG_ARCH_VIRT
 - CONFIG_CPU_SPECTRE is select by CONFIG_CPU_V7
 - CONFIG_TIMER_OF is now a arch default
 - CONFIG_TIMER_PROBE is select by CONFIG_TIMER_OF

The following options should probably be moved to generic config

 - CONFIG_MIGRATION is a default on option
 - CONFIG_TREE_SRCU is a default on option for !PREEMPT && SMP system
 - CONFIG_RCU_NEED_SEGCBLIST

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>