boot/uboot: fix custom repo error message

When using a custom git or mercurial repository for u-boot the error message
indicating a version had not been provided incorrectly stated that the URL was
missing. Update the error message to indicate that it's the version that's
missing.

Signed-off-by: Garret Kelly <garret.kelly@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 1271867831a9fcf8e7ef52a1691386c63205474c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/uboot/uboot.mk

@@ -510,7 +510,7 @@ ifeq ($(call qstrip,$(BR2_TARGET_UBOOT_CUSTOM_REPO_URL)),)
 $(error No custom U-Boot repository URL specified. Check your BR2_TARGET_UBOOT_CUSTOM_REPO_URL setting)
 endif # qstrip BR2_TARGET_UBOOT_CUSTOM_CUSTOM_REPO_URL
 ifeq ($(call qstrip,$(BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION)),)
-$(error No custom U-Boot repository URL specified. Check your BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION setting)
+$(error No custom U-Boot repository version specified. Check your BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION setting)
 endif # qstrip BR2_TARGET_UBOOT_CUSTOM_CUSTOM_REPO_VERSION
 endif # BR2_TARGET_UBOOT_CUSTOM_GIT || BR2_TARGET_UBOOT_CUSTOM_HG