spi25: Remove dead increment

Value stored in 'pos' is never read.

Found-by: scan-build 7.0.1-8
Change-Id: I9a70593f182d7558e71e831fc2b834ac58a25b2a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/34404
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/spi25.c b/spi25.c
index 36f265a..2a1d492 100644
--- a/spi25.c
+++ b/spi25.c
@@ -782,7 +782,6 @@
 	if (pos < start + len) {
 		if (spi_chip_write_1(flash, buf + pos - start, pos, pos % 2))
 			return SPI_GENERIC_ERROR;
-		pos += pos % 2;
 	}
 
 	return 0;