x86, boot: Pass cmd_line_ptr with unsigned long instead

boot/compressed/misc.c is used for bzImage in 64bit and 32bit, and
cmd_line_ptr could point to buffer that is above 4g, cmd_line_ptr
should be 64bit otherwise high 32bit will be capped out.

So need to change data type to unsigned long, that will be 64bit get
correct address of command line buffer.

And it is still ok with 32bit bzImage, because unsigned long on 32bit kernel
is still 32bit.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-19-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>