brcmfmac: fix firmware trap while dumping obss stats

When doing dump_survey, host will call "dump_obss" iovar to firmware
side. Host need to make sure the HW clock in dongle is on, or there is
high probability that firmware gets trap because register or shared
memory access failed. To fix this, we disable mpc when doing dump obss
and set it back after that.

[28350.512799] brcmfmac: brcmf_dump_obss: dump_obss error (-52)
[28743.402314] ieee80211 phy0: brcmf_fw_crashed: Firmware has halted or
crashed
[28745.869430] brcmfmac: brcmf_sdio_bus_rxctl: resumed on timeout
[28745.877546] brcmfmac: brcmf_sdio_checkdied: firmware trap in dongle

Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Chi-hsien Lin <chi-hsien.lin@infineon.com>
Signed-off-by: Ian Lin <ian.lin@infineon.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220929012527.4152-3-ian.lin@infineon.com