PROV: Build the main FIPS module code with FIPS_MODE defined

Without that, its main source wasn't compiled correctly.

Fixes #11089

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/11090)

providers/build.info

@@ -101,6 +101,7 @@ SUBDIRS=fips
 $FIPSGOAL=fips
 DEPEND[$FIPSGOAL]=$LIBIMPLEMENTATIONS $LIBFIPS
 INCLUDE[$FIPSGOAL]=../include
+DEFINE[$FIPSGOAL]=FIPS_MODE
 IF[{- defined $target{shared_defflag} -}]
   SOURCE[$FIPSGOAL]=fips.ld
   GENERATE[fips.ld]=../util/providers.num