x86: Enable non-temporal memset for Hygon processors

x86: Enable non-temporal memset for Hygon processors

This patch uses 'Avoid_Non_Temporal_Memset' flag to access
the non-temporal memset implementation for hygon processors.

Test Results:

hygon1 arch
x86_memset_non_temporal_threshold = 8MB
size                          new performance time / old performance time
1MB                           0.994
4MB                           0.996
8MB                           0.670
16MB                          0.343
32MB                          0.355

hygon2 arch
x86_memset_non_temporal_threshold = 8MB
size                          new performance time / old performance time
1MB                           1
4MB                           1
8MB                           1.312
16MB                          0.822
32MB                          0.830

hygon3 arch
x86_memset_non_temporal_threshold = 8MB
size                          new performance time / old performance time
1MB                           1
4MB                           0.990
8MB                           0.737
16MB                          0.390
32MB                          0.401

For hygon arch with this patch, non-temporal stores can improve
performance by 20% - 65%.

Signed-off-by: Feifei Wang <wangfeifei@hygon.cn>
Reviewed-by: Jing Li <lijing@hygon.cn>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>