It report error message while suspend/resume test.
dmesg log:
[  150.749962] ath10k_sdio mmc1:0001:1: hif read32 not supported
[  150.755728] ath10k_sdio mmc1:0001:1: failed to set coverage class: expected integer microsecond value in register

Reason is sdio chip does not support set_coverage_class as well as
pcie chip, remove the set_coverage_class handler will avoid it.

callstack of the error message:
OUTLINED_FUNCTION_6+0xc/0x14 [ath10k_core]
ath10k_mac_op_set_coverage_class+0x2c/0x40 [ath10k_core]
ieee80211_reconfig+0x5d0/0x108c [mac80211]
ieee80211_resume+0x34/0x6c [mac80211]
wiphy_resume+0xbc/0x13c [cfg80211]
dpm_run_callback+0xa4/0x168
device_resume+0x1d4/0x200
async_resume+0x1c/0x34
async_run_entry_fn+0x48/0xf8
process_one_work+0x178/0x2f8
worker_thread+0x1d8/0x2cc
kthread+0x11c/0x12c
ret_from_fork+0x10/0x18

the error log will not happen after this patch applied.

Tested with QCA6174 SDIO with firmware
WLAN.RMH.4.4.1-00007-QCARMSWP-1.
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>