KVM: arm64: fix override-init warnings in W=1 builds

Add -Wno-override-init to the build flags for sys_regs.c,
handle_exit.c, and switch.c to fix warnings like the following:

arch/arm64/kvm/hyp/vhe/switch.c:271:43: warning: initialized field overwritten [-Woverride-init]
271 | [ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32,
|

Signed-off-by: Sebastian Ott <[e-mail]>
Reviewed-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Oliver Upton <[e-mail]>

arch/arm64/kvm/Makefile

···
 obj-$(CONFIG_KVM) += kvm.o
 obj-$(CONFIG_KVM) += hyp/
 
+CFLAGS_sys_regs.o += -Wno-override-init
+CFLAGS_handle_exit.o += -Wno-override-init
+
 kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 inject_fault.o va_layout.o handle_exit.o \
 	 guest.o debug.o reset.o sys_regs.o stacktrace.o \

arch/arm64/kvm/hyp/nvhe/Makefile

···
 lib-objs := clear_page.o copy_page.o memcpy.o memset.o
 lib-objs := $(addprefix ../../../lib/, $(lib-objs))
 
+CFLAGS_switch.nvhe.o += -Wno-override-init
+
 hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
 	 hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
 	 cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o

arch/arm64/kvm/hyp/vhe/Makefile

···
 asflags-y := -D__KVM_VHE_HYPERVISOR__
 ccflags-y := -D__KVM_VHE_HYPERVISOR__
 
+CFLAGS_switch.o += -Wno-override-init
+
 obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o
 obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
 	 ../fpsimd.o ../hyp-entry.o ../exception.o