GCC4.6: Squash warnings in ks8695eth.c

ks8695eth.c:199:2: warning: format '%x' expects type 'unsigned int', but
argument 4 has type 'volatile void *'

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>