Commit c1d7e01d ("ipc: use Kconfig options for
__ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION") replaced the
__ARCH_WANT_COMPAT_IPC_PARSE_VERSION token with a corresponding Kconfig
option instead.

This patch updates arm64 to use the latter, rather than #define an
unused token.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>