makefile: Remove unused variable FD_IMG_BASE

Signed-off-by: Marco Franssen <marco.franssen@gmail.com>

Author: marcofranssen

Makefile

@@ -13,7 +13,6 @@ FB_IMG ?= ghcr.io/fluent/fluent-operator/fluent-bit:v${FB_VERSION}
 FB_IMG_DEBUG ?= ghcr.io/fluent/fluent-operator/fluent-bit:v${FB_VERSION}-debug
 FD_IMG ?= ghcr.io/fluent/fluent-operator/fluentd:v1.19.1
 FO_IMG ?= kubesphere/fluent-operator:$(VERSION)
-FD_IMG_BASE ?= ghcr.io/fluent/fluent-operator/fluentd:v1.17.0-arm64-base
 
 ARCH ?= arm64