Bus Pirate buffer management revamp

The buffer management of the Bus Pirate driver has been revamped to use
grow-only buffers with a reasonable initial default size so realloc()
will not have to be called in normal operation. A side effect is the
ability to switch to a static buffer without major hassle.
Handle OOM gracefully.

Corresponding to flashrom svn r1541.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Patrick Georgi <patrick@georgi-clan.de>

flash.h

@@ -36,6 +36,7 @@
 #define ERROR_PTR ((void*)-1)
 
 /* Error codes */
+#define ERROR_OOM	-100
 #define TIMEOUT_ERROR	-101
 
 typedef unsigned long chipaddr;