spd: Fix math bug in spd_read_from_cbfs()

The boundary check in spd_read_from_cbfs() should use <= instead of <
since it's sanity checking a count rather than an offset for the
bytes to be read.

BUG=chromium:580794
BRANCH=none
TEST=none

Change-Id: I85bab6fce1982a0b8312e9485f0c1bd9cf9de9cd
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/327991
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
diff --git a/lib/spd/spd.c b/lib/spd/spd.c
index 6d87726..8b08c51 100644
--- a/lib/spd/spd.c
+++ b/lib/spd/spd.c
@@ -289,7 +289,7 @@
 		goto out;
 	}
 
-	MOSYS_CHECK((spd_index * 256) + reg + num_bytes_to_read <
+	MOSYS_CHECK((spd_index * 256) + reg + num_bytes_to_read <=
 							num_spd * 256);
 	spd_offset = ntohl(file->offset) + (spd_index * 256);