fix(cpufeat): use helpers for RNDR instead of inline assembly

This gives backwards compatibility when FEAT_RNG isn't
understood/enabled.

Change-Id: Ic39eda6432cd27bae8a722e2a17da8ac35ffbae4
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
1 file changed