Documentation/features: Use loongarch instead of loong

Documentation/features: Use loongarch instead of loong

The official arch name is LoongArch [1], we should use small letter
loongarch instead of loong in Documentation/features, just use the
features-refresh.sh to refresh all the related files.

[1] https://www.kernel.org/doc/html/latest/loongarch/index.html

Fixes: 5860800e8696 ("Documentation/features: Update the arch support status files")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1670156327-9631-3-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>