package/busybox: correctly set BUSYBOX_KCONFIG_SUPPORTS_DEFCONFIG

Commit e6b3913cfc converted busybox to the generic kconfig help text
infrastructure, but set the wrong variable to flag that it doesn't
support defconfig files. Fix that.
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

buildroot-2021.05/package/busybox/busybox.mk

@@ -103,7 +103,7 @@ ifndef BUSYBOX_CONFIG_FILE
 BUSYBOX_CONFIG_FILE = $(call qstrip,$(BR2_PACKAGE_BUSYBOX_CONFIG))
 endif
 
-BUSYBOX_KCONFIG_HAS_DEFCONFIG = NO
+BUSYBOX_KCONFIG_SUPPORTS_DEFCONFIG = NO
 BUSYBOX_KCONFIG_FILE = $(BUSYBOX_CONFIG_FILE)
 BUSYBOX_KCONFIG_FRAGMENT_FILES = $(call qstrip,$(BR2_PACKAGE_BUSYBOX_CONFIG_FRAGMENT_FILES))
 BUSYBOX_KCONFIG_EDITORS = menuconfig xconfig gconfig