compat: ARM64: always include asm-generic/compat.h

In order to use compat_* type defininitions in device drivers
outside of CONFIG_COMPAT, move the inclusion of asm-generic/compat.h
ahead of the #ifdef.

All other architectures already do this.

Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>