Check the JEDEC vendor ID for correct parity

Flash chips which can be detected by JEDEC probe routines all have
vendor IDs with correct parity. Use a parity check as additional hint
whether a vendor ID makes sense. Note: Device IDs have no parity
requirements whatsoever.

Corresponding to flashrom svn r231 and coreboot v2 svn r3308.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Peter Stuge <peter@stuge.se>
diff --git a/flash.h b/flash.h
index 67f49c6..37d7dc0 100644
--- a/flash.h
+++ b/flash.h
@@ -396,6 +396,7 @@
 void it8716f_spi_page_program(int block, uint8_t *buf, uint8_t *bios);
 
 /* jedec.c */
+uint8_t oddparity(uint8_t val);
 void toggle_ready_jedec(volatile uint8_t *dst);
 void data_polling_jedec(volatile uint8_t *dst, uint8_t data);
 void unprotect_jedec(volatile uint8_t *bios);