lib/edid.c: Avoid static analysis error for unused value

Within procedure cea_hdmi_block, the variable "b" is used as an index into
a buffer of EDID bytes. At the end, it's incremented but not used, thus
causing a static analysis error. Add a "(void)b;" at the end to avoid the
static analysis error.

BUG=b:112253891
TEST=Build and boot grunt.

Change-Id: Ibd0b4a21bf82fcc46a627bc75564a850b7374989
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/27929
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/lib/edid.c

@@ -817,8 +817,9 @@ cea_hdmi_block(struct edid *out, unsigned char *x)
 				 * (optionally: 3D_Detail_X and reserved)
 				 */
 			}
-
 		}
+		/* Tell static analysis we know index b is left unused. */
+		(void)b;
 	}
 }