busybox: fix LTO compiler flags

When doing LTO builds, the target related CFLAGS need to be passed to the
linker, so that they are considered for target code generation.
Pass TARGET_CFLAGS in EXTRA_LDFLAGS to ensure that this is handled properly.

Fixes: #17200
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit e6ce868c3a)

package/utils/busybox/Makefile

@@ -111,7 +111,7 @@ endif
 MAKE_VARS :=
 MAKE_FLAGS += \
 	EXTRA_CFLAGS="$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)" \
-	EXTRA_LDFLAGS="$(TARGET_LDFLAGS)" \
+	EXTRA_LDFLAGS="$(TARGET_LDFLAGS) $(TARGET_CFLAGS)" \
 	LDLIBS="$(LDLIBS)" \
 	LD="$(TARGET_CC)" \
 	SKIP_STRIP=y