wifi: rtw88: 8822b: Avoid WARNING in rtw8822b_config_trx_mode()

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtw88: 8822b: Avoid WARNING in rtw8822b_config_trx_mode()

rtw8822b_set_antenna() can be called from userspace when the chip is
powered off. In that case a WARNING is triggered in
rtw8822b_config_trx_mode() because trying to read the RF registers
when the chip is powered off returns an unexpected value.

Call rtw8822b_config_trx_mode() in rtw8822b_set_antenna() only when
the chip is powered on.

------------[ cut here ]------------
write RF mode table fail
WARNING: CPU: 0 PID: 7183 at rtw8822b.c:824 rtw8822b_config_trx_mode.constprop.0+0x835/0x840 [rtw88_8822b]
CPU: 0 UID: 0 PID: 7183 Comm: iw Tainted: G W OE 6.17.5-arch1-1 #1 PREEMPT(full) 01c39fc421df2af799dd5e9180b572af860b40c1
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: LENOVO 82KR/LNVNB161216, BIOS HBCN18WW 08/27/2021
RIP: 0010:rtw8822b_config_trx_mode.constprop.0+0x835/0x840 [rtw88_8822b]
Call Trace:
<TASK>
rtw8822b_set_antenna+0x57/0x70 [rtw88_8822b 370206f42e5890d8d5f48eb358b759efa37c422b]
rtw_ops_set_antenna+0x50/0x80 [rtw88_core 711c8fb4f686162be4625b1d0b8e8c6a5ac850fb]
ieee80211_set_antenna+0x60/0x100 [mac80211 f1845d85d2ecacf3b71867635a050ece90486cf3]
nl80211_set_wiphy+0x384/0xe00 [cfg80211 296485ee85696d2150309a6d21a7fbca83d3dbda]
? netdev_run_todo+0x63/0x550
genl_family_rcv_msg_doit+0xfc/0x160
genl_rcv_msg+0x1aa/0x2b0
? __pfx_nl80211_pre_doit+0x10/0x10 [cfg80211 296485ee85696d2150309a6d21a7fbca83d3dbda]
? __pfx_nl80211_set_wiphy+0x10/0x10 [cfg80211 296485ee85696d2150309a6d21a7fbca83d3dbda]
? __pfx_nl80211_post_doit+0x10/0x10 [cfg80211 296485ee85696d2150309a6d21a7fbca83d3dbda]
? __pfx_genl_rcv_msg+0x10/0x10
netlink_rcv_skb+0x59/0x110
genl_rcv+0x28/0x40
netlink_unicast+0x285/0x3c0
? __alloc_skb+0xdb/0x1a0
netlink_sendmsg+0x20d/0x430
____sys_sendmsg+0x39f/0x3d0
? import_iovec+0x2f/0x40
___sys_sendmsg+0x99/0xe0
? refill_obj_stock+0x12e/0x240
__sys_sendmsg+0x8a/0xf0
do_syscall_64+0x81/0x970
? do_syscall_64+0x81/0x970
? ksys_read+0x73/0xf0
? do_syscall_64+0x81/0x970
? count_memcg_events+0xc2/0x190
? handle_mm_fault+0x1d7/0x2d0
? do_user_addr_fault+0x21a/0x690
? exc_page_fault+0x7e/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
---[ end trace 0000000000000000 ]---