Fix part number for SPI isolator

The new part number is in the correct package.

Change-Id: Idd8321c2b79a965589159aebe8402f79b01b7319
diff --git a/motors/uart_schematic/uart-spi.sch b/motors/uart_schematic/uart-spi.sch
index c19457d..beb4010 100644
--- a/motors/uart_schematic/uart-spi.sch
+++ b/motors/uart_schematic/uart-spi.sch
@@ -59,7 +59,7 @@
 T 66100 54500 5 10 0 1 0 0 1
 footprint=SO16W
 T 64400 51500 5 10 0 0 0 0 1
-pn=SI8641BA-B-IUR
+pn=SI8641BB-B-ISR
 }
 C 64200 53200 1 90 0 generic-power.sym
 {