Eliminate the .eh_frame sections from the aarch64 vmlinux and kernel modules

By default the aarch64 gcc generates .eh_frame sections.  Unlike
.debug_frame sections, the .eh_frame sections are loaded into memory
when the associated code is loaded.  On an example kernel being built
with this default the .eh_frame section in vmlinux used an extra 1.7MB
of memory.  The x86 disables the creation of the .eh_frame section.
The aarch64 should probably do the same to save some memory.
Signed-off-by: NWilliam Cohen <wcohen@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/Makefile

@@ -27,6 +27,7 @@ $(warning LSE atomics not supported by binutils)
 endif
 
 KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr)
+KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
 KBUILD_AFLAGS	+= $(lseinstr)
 
 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)