gptfdisk: add error handling to for loop

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gptfdisk/gptfdisk.mk

@@ -37,7 +37,7 @@ endef
 
 define GPTFDISK_INSTALL_TARGET_CMDS
 	for i in $(GPTFDISK_TARGETS_y); do \
-		$(INSTALL) -D -m 0755 $(@D)/$$i $(TARGET_DIR)/usr/sbin/$$i; \
+		$(INSTALL) -D -m 0755 $(@D)/$$i $(TARGET_DIR)/usr/sbin/$$i || exit 1; \
 	done
 endef