mt76: mt7615: fix monitor mode tear down crash

mt76: mt7615: fix monitor mode tear down crash

[  103.451600] CPU 3 Unable to handle kernel paging request at virtual address 00000003, epc == 8576591c, ra == 857659f0
[  103.462226] Oops[#1]:
[  103.464499] CPU: 3 PID: 9247 Comm: ifconfig Tainted: G        W         5.4.143 #0
[  103.472031] $ 0   : 00000000 00000001 83be3854 00000000
[  103.477239] $ 4   : 8102a374 8102a374 8102f0b0 00000200
[  103.482444] $ 8   : 0000002d 000001e4 64373765 5d206337
[  103.487647] $12   : 00000000 00000005 00000000 0006d1df
[  103.492853] $16   : 83be3848 853838a8 8743d600 00010000
[  103.498059] $20   : 00000000 00000000 8553dec0 0000007f
[  103.503266] $24   : 00000003 80382084
[  103.508472] $28   : 831d4000 831d5bc0 00000001 857659f0
[  103.513678] Hi    : 00000122
[  103.516543] Lo    : d1768000
[  103.519452] epc   : 8576591c mt7615_mcu_add_bss+0xd0/0x3c0 [mt7615_common]
[  103.526306] ra    : 857659f0 mt7615_mcu_add_bss+0x1a4/0x3c0 [mt7615_common]
[  103.533232] Status: 11007c03 KERNEL EXL IE
[  103.537402] Cause : 40800008 (ExcCode 02)
[  103.541389] BadVA : 00000003
[  103.544253] PrId  : 0001992f (MIPS 1004Kc)
[  103.797086] Call Trace:
[  103.799562] [<8576591c>] mt7615_mcu_add_bss+0xd0/0x3c0 [mt7615_common]
[  103.806082] [<85760a14>] mt7615_remove_interface+0x74/0x1e0 [mt7615_common]
[  103.813280] [<85603fcc>] drv_remove_interface+0x2c/0xa0 [mac80211]
[  103.819612] [<8561a8e4>] ieee80211_del_virtual_monitor.part.22+0x74/0xe8 [mac80211]
[  103.827410] [<8561b7f0>] ieee80211_do_stop+0x4a4/0x8a0 [mac80211]
[  103.833671] [<8561bc00>] ieee80211_stop+0x14/0x24 [mac80211]
[  103.839405] [<8045a328>] __dev_close_many+0x9c/0x10c
[  103.844364] [<80463de4>] __dev_change_flags+0x16c/0x1e4
[  103.849569] [<80463e84>] dev_change_flags+0x28/0x70
[  103.854440] [<80521e54>] devinet_ioctl+0x280/0x774
[  103.859222] [<80526248>] inet_ioctl+0xa4/0x1c8
[  103.863674] [<80436830>] sock_ioctl+0x2d8/0x4bc
[  103.868201] [<801adbb4>] do_vfs_ioctl+0xb8/0x7c0
[  103.872804] [<801ae30c>] ksys_ioctl+0x50/0xb4
[  103.877156] [<80014598>] syscall_common+0x34/0x58

Fixes: 04b8e65922f63 ("mt76: add mac80211 driver for MT7615 PCIe-based chipsets")
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>