crypto: arm64/aes-ccm - reduce NEON begin/end calls for common case

AES-CCM (as used in WPA2 CCMP, for instance) typically involves
authenticate-only data, and operates on a single network packet, and so
the common case is for the authenticate, en/decrypt and finalize SIMD
helpers to all be called exactly once in sequence. Since
kernel_neon_end() now involves manipulation of the preemption state as
well as the softirq mask state, let's reduce the number of times we are
forced to call it to only once if we are handling this common case.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>