arm64: extable: cleanup redundant extable type EX_TYPE_FIXUP

Currently, extable type EX_TYPE_FIXUP is no place to use, We can safely
remove it.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220621072638.1273594-7-tongtiangen@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>