bzip2/lzma/gzip: pre-boot malloc doesn't return NULL on failure

The trivial malloc implementation used in the pre-boot environment by the
decompressors returns a bad pointer on failure (falling through after
calling error).  This is doubly wrong - the callers expect malloc to
return NULL on failure, second the error function is intended to be
used by the decompressors to propagate errors to *their* callers.  The
decompressors have no access to any state set by the error function.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
LKML-Reference: <4b26b1ef.hIInb2AYPMtImAJO%phillip@lougher.demon.co.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

include/linux/decompress/mm.h

@@ -25,7 +25,7 @@ static void *malloc(int size)
 	void *p;
 
 	if (size < 0)
-		error("Malloc error");
+		return NULL;
 	if (!malloc_ptr)
 		malloc_ptr = free_mem_ptr;
 
@@ -35,7 +35,7 @@ static void *malloc(int size)
 	malloc_ptr += size;
 
 	if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
-		error("Out of memory");
+		return NULL;
 
 	malloc_count++;
 	return p;