makefile: add missing semicolons

On some distributions, as Debian GNU 11, this targets fails
with errors.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
diff --git a/scripts/Makefile.autoconf b/scripts/Makefile.autoconf
index 0bfc1b2..8a3efdb 100644
--- a/scripts/Makefile.autoconf
+++ b/scripts/Makefile.autoconf
@@ -61,7 +61,7 @@
 			if [ -n "${KCONFIG_IGNORE_DUPLICATES}" ] ||			\
 			   ! grep -q "$${line%=*}=" include/config/auto.conf; then	\
 				echo "$$line";						\
-			fi								\
+			fi;								\
 		done > $@
 
 quiet_cmd_u_boot_cfg = CFG     $@