wil6210: use inline functions for register access

Replace macros like "R", "W", "S", "C", defined multiple times,
with inline functions "wil_[rwsc]".

Use "readl" and "writel" instead of "ioread32" and "iowrite32"
since it is granted that memory transactions are used,
not port ones like IN/OUT

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>