zlib: Replace negative logic in Makefile with positive

Positive logic is easier to read and understand than something
like 'if not option=yes then foo else bar'.

Signed-off-by: Michael Roth <mroth@nessie.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/zlib/zlib.mk

@@ -18,14 +18,14 @@ $(ZLIB_DIR)/.patched: $(DL_DIR)/$(ZLIB_SOURCE)
 	$(CONFIG_UPDATE) $(@D)
 	touch $@
 
-ifneq ($(BR2_PREFER_STATIC_LIB),y)
-ZLIB_PIC := -fPIC
-ZLIB_SHARED := --shared
-ZLIB_TARGET := $(TARGET_DIR)/usr/lib/libz.so
-else
+ifeq ($(BR2_PREFER_STATIC_LIB),y)
 ZLIB_PIC :=
 ZLIB_SHARED :=
 ZLIB_TARGET := $(STAGING_DIR)/usr/lib/libz.a
+else
+ZLIB_PIC := -fPIC
+ZLIB_SHARED := --shared
+ZLIB_TARGET := $(TARGET_DIR)/usr/lib/libz.so
 endif
 
 $(ZLIB_DIR)/.configured: $(ZLIB_DIR)/.patched