xbmk: remove the setcfg function

this allows me to remove several eval calls, and the
errors relating to configs can now show exactly which
function they occured in, allowing for easier debugging.

once again, eval should be used sparingly if at all.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/rom.sh

@@ -45,7 +45,12 @@ mkpayload_grub()
 	grub_modules=""
 	grub_install_modules=""
 
-	$dry eval "`setcfg "$grubdata/module/$tree"`"
+	if [ "$dry" = ":" ]; then
+		return 0
+	fi
+
+	. "$grubdata/module/$tree" || \
+	    err "Can't read '$grubdata/module/$tree'" "mkpayload_grub" "$@"
 
 	$dry x_ rm -f "$srcdir/grub.elf"