wifi: rtw89: add counters of register-based H2C/C2H

wifi: rtw89: add counters of register-based H2C/C2H

The register-based H2C/C2H are used to exchange information between driver
and firmware, but only apply to narrow area because its data size is
smaller than regular packet-based H2C/C2H.

This kind of H2C/C2H must be paired. To identify if any H2C/C2H is missing,
update counters to help diagnose this kind of problems.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230316063956.71687-1-pkshih@realtek.com