Revert "staging: r8188eu: use in-kernel ieee channel"

Revert "staging: r8188eu: use in-kernel ieee channel"

This reverts commit f37ec450b7b9f710b35d795e92f7c9e1b40484eb as changing
rtw_ieee80211_channel to ieee80211_channel causes a memcpy bug as
reported in:
	https://lore.kernel.org/linux-staging/67e2d10b-7f0f-9c5a-ce31-376b83ffba9e@gmail.com/
due to their size differences.

Fixes: f37ec450b7b9 ("staging: r8188eu: use in-kernel ieee channel")
Reported-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Solomon Tan <wjsota@gmail.com>
Link: https://lore.kernel.org/r/20220425052802.2419-1-wjsota@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>