Revert "fmt: bump default version check"

This reverts commit 80abd8b7.

Reason for revert: should now work with {fmt} 6

Change-Id: I9e7f287a8fb79e33d343eadbceb84c4290629699

contrib/src/fmt/rules.mak

@@ -3,7 +3,7 @@ FMT_VERSION := 9.0.0
 FMT_URL := https://github.com/fmtlib/fmt/archive/$(FMT_VERSION).tar.gz
 
 PKGS += fmt
-ifeq ($(call need_pkg,'fmt >= ${FMT_VERSION}'),)
+ifeq ($(call need_pkg,'fmt >= 6.0'),)
 PKGS_FOUND += fmt
 endif