Remove files added by b51f459a2098622c31ed54f5c1bf0e03efce403b.
The util/config.c conflicts with wpa_supplicant/config.c causing
the linker error.

The proper approach would have been to prepare the wpa build to
build the various subdirectories into .a libraries. SRCS makes no
distinction between files of the same name. The MFV accounted for this
but the revert failed to remove the additional files, including the
conflicting utils/config.c.

b51f459a2098622c31ed54f5c1bf0e03efce403b resulted in a mismerge
due to having to do a remerge because my tree was over a week out of
date. Changes that were made to fix the build were lost in the remerge
resulting in build errors that were fixed a week ago.

This is the April update to vendor/wpa committed upstream
2021/04/07.

This is MFV efec8223892b3e677acb46eae84ec3534989971f.

Suggested by:		philip
Reviewed by:		philip
MFC after:		2 months
Differential Revision:	https://reviews.freebsd.org/D29744