zlib/gunzip: Use WATCHDOG_RESET macro

As usually done in U-Boot, the watchdog_reset code is called via a
macro (WATCHDOG_RESET). In zlib.c this was done differently, by using
a function pointer which is initialized with WATCHDOG_RESET upon watchdog
usage or with NULL otherwise. This patch now uses the plain
WATCHDOG_RESET macros to call the function resulting in slightly smaller
U-Boot images and simpler code.

U-Boot code size reduction:

PowerPC board with watchdog support (lwmon5):
-> 80 bytes smaller image size

PowerPC board without watchdog support (sequoia):
-> 112 bytes smaller image size

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>

lib/gunzip.c

@@ -96,11 +96,6 @@ int zunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp,
 
 	s.zalloc = zalloc;
 	s.zfree = zfree;
-#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
-	s.outcb = (cb_func)WATCHDOG_RESET;
-#else
-	s.outcb = Z_NULL;
-#endif	/* CONFIG_HW_WATCHDOG */
 
 	r = inflateInit2(&s, -MAX_WBITS);
 	if (r != Z_OK) {