build: support arch-specific compiling for Neoverse N1

build: support arch-specific compiling for Neoverse N1

Enable arch-specific compiling and dynamic optimal function selection
for Arm Neoverse-N1.

Support for -march=armv8.2-a+crc+crypto -mtune=neoverse-n1 for
Neoverse-N1 is added starting from gcc-9.2.0

                    without change  with change improvement
[L2 - 1x flows]     11.00 Mpps      11.46 Mpps  4%
[L2 - 10Kx flows]   6.83 Mpps       7.17 Mpps   5%
[L3 - 1x flows]     10.39 Mpps      10.78 Mpps  3.7%
[L3 - 10Kx flows]   6.67 Mpps       7.19 Mpps   7.8%

Type: feature

Change-Id: I5d24d17820b3dd6909b913202e8c31fc7d48650f
Signed-off-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Jieqiang Wang <Jieqiang.Wang@arm.com>
Reviewed-by: Govindarajan Mohandoss <Govindarajan.Mohandoss@arm.com>