[PATCH] Fix ppc32 zImage inflate

The recent zlib update (commit 4f3865fb)
broke ppc32 zImage decompression as it tries to decompress to address zero
and the updated zlib_inflate checks that strm->next_out isn't a null
pointer.

This little patch fixes it.

[rpurdie@rpsys.net: add comment]
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Tom Rini <trini@kernel.crashing.org>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>