Revert "arm64: alternatives: add enable parameter to conditional asm macros"

Revert "arm64: alternatives: add enable parameter to conditional asm macros"

Commit fb8fd70498b61 ("arm64: alternatives: add enable parameter to
conditional asm macros") extended the alternative assembly macros.
Unfortunately this does not really work as one would expect, as the
enable parameter in fact correctly protects the alternative section
magic, but not the actual code sequences.
This results in having both the original instruction(s) _and_  the
alternative ones, if enable if false.
Since there is no user of this macros anyway, just revert it.

This reverts commit fb8fd70498b61ad828868af9009e076ed740cc52.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>