arm64: Select ARCH_WANT_FRAME_POINTERS

The compiler generates framepointers by default anyway but this is to
avoid a kbuild warning.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/Kconfig

@@ -2,6 +2,7 @@ config ARM64
 	def_bool y
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
+	select ARCH_WANT_FRAME_POINTERS
 	select ARM_AMBA
 	select CLONE_BACKWARDS
 	select COMMON_CLK