rtw89: rename vif_maintain to role_maintain

The H2C_FUNC_MAC_FWROLE_MAINTAIN also maintains the roles of all connected
stations; not just the role of VIF. So, I correct the name, but don't
change the logic at all.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220107034239.22002-9-pkshih@realtek.com