zlib: Add further watchdog reset calls

Patch 253cb831 [zlib: add watchdog reset call] added already a few
watchdog reset calls to the new zlib U-Boot port. But on some boards
this is not enough. Additional calls are needed on boards with
short watchdog timeouts.

This was detected and tested on the lwmon5 board with a very short
watchdog timeout. Without this patch, the board resets during Linux
kernel decompression. With it, the decompression succeeds.

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