Fix timing of SPI status register writes (WRSR)

SPI write status register (WRSR) may take longer than 100 ms, and it
makes sense to poll for completion in 10 ms steps until 5 s are over.
This patch complements r1115.

Corresponding to flashrom svn r1201.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Joshua Roys <roysjosh@gmail.com>

flash.h

@@ -35,6 +35,9 @@
 
 #define ERROR_PTR ((void*)-1)
 
+/* Error codes */
+#define TIMEOUT_ERROR	-101
+
 typedef unsigned long chipaddr;
 
 int register_shutdown(void (*function) (void *data), void *data);