Aarch64: Add new memset for Qualcomm's oryon-1 core

Qualcom's new core, oryon-1, has a different characteristics for
memset than the current versions of memset. For non-zero, larger
sizes, using GPRs rather than the SIMD stores is ~30% faster.
For even larger sizes, using the nontemporal stores is needed
not to polute the L1/L2 caches.

For zero values, using `dc zva` should be used. Since we
know the size will always be 64 bytes, we don't need to figure
out the size there.

I started with the emag memset and added back the `dc zva` code.

Changes since v1:
* v3: Fix comment formating

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>