wifi: rtw89: regd: judge UNII-4 according to BIOS and chip

For realtek regulatory, there are following two kinds of configurations
to determine whether to allow UNII-4 band, i.e. 5.9GHz channels.

1. default setting according to whether chip support it or not
2. evaluate realtek ACPI DSM with RTW89_ACPI_DSM_FUNC_59G_EN (func. 6)

If (1) is false, we won't try (2) and just disallow UNII-4. Otherwise,
if (2) is not supported or returns a non-specific value, we follow the
default setting either. Besides, this commit aims to add decision logic
in rtw89 regulatory. Actually, driver doesn't register UNII-4 yet. That
will be handled by another commit.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230508081211.38760-3-pkshih@realtek.com