staging: rtl8188eu: remove all DBG_88E calls from core/rtw_xmit.c

staging: rtl8188eu: remove all DBG_88E calls from core/rtw_xmit.c

Remove all DBG_88E calls from core/rtw_xmit.c as this macro is
unnecessary, and many of these calls are dubious in terms of necessity.
Removing all calls will ultimately allow the removal of the macro
itself.

Also remove static rtw_sctx_chk_warning_status function, as it no longer
has any callers.

Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210615001507.1171-3-phil@philpotter.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>