arm64: assembler: remove conditional NEON yield macros

The users of the conditional NEON yield macros have all been switched to
the simplified cond_yield macro, and so the NEON specific ones can be
removed.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210302090118.30666-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>