arm64/kexec: Enable kexec in the arm64 defconfig

Signed-off-by: NGeoff Levand <geoff@infradead.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/configs/defconfig

@@ -70,6 +70,7 @@ CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CMA=y
 CONFIG_XEN=y
+CONFIG_KEXEC=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_COMPAT=y
 CONFIG_CPU_IDLE=y