Add write support

Speed up reads by a factor of 4 by switching block size from 4 to 16.
Add support for 4 byte RDID.
Add USB error decoding via usb_strerror.

Corresponding to flashrom svn r879.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
diff --git a/spi.c b/spi.c
index aaf7d88..e1ab2ea 100644
--- a/spi.c
+++ b/spi.c
@@ -335,6 +335,9 @@
 #if BUSPIRATE_SPI_SUPPORT == 1
 	case SPI_CONTROLLER_BUSPIRATE:
 #endif
+#if DEDIPROG_SUPPORT == 1
+	case SPI_CONTROLLER_DEDIPROG:
+#endif
 		return probe_spi_rdid_generic(flash, 4);
 	default:
 		printf_debug("4b ID not supported on this SPI controller\n");