boot/barebox: update condition for custom tarball management

This patch updates the condition to handle custom tarballs as specified by
the configuration. This change is made to have cleaner condition and for
consistency.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

boot/barebox/barebox.mk

@@ -17,7 +17,7 @@ define inner-barebox-package
 
 $(1)_VERSION = $$(call qstrip,$$(BR2_TARGET_BAREBOX_VERSION))
 
-ifeq ($$($(1)_VERSION),custom)
+ifeq ($$(BR2_TARGET_BAREBOX_CUSTOM_TARBALL),y)
 # Handle custom Barebox tarballs as specified by the configuration
 $(1)_TARBALL = $$(call qstrip,$$(BR2_TARGET_BAREBOX_CUSTOM_TARBALL_LOCATION))
 $(1)_SITE = $$(patsubst %/,%,$$(dir $$($(1)_TARBALL)))