autoport/bd82x6x: Fix off-by-one error

Change-Id: Ibd5c8a1364ab183f72e12cc9b450a36200fe3fde
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/10371
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>

util/autoport/bd82x6x.go

@@ -105,7 +105,7 @@ func ich9GetFlashSize(ctx Context) {
 		highflkb := uint32(0)
 		for reg := uint16(0); reg < 5; reg++ {
 			fl := (inteltool.RCBA[0x3854+4*reg] >> 16) & 0x1fff
-			flkb := fl << 2
+			flkb := (fl + 1) << 2
 			if flkb > highflkb {
 				highflkb = flkb
 			}