Fixed interrupts on port B not being cleared

Author: Donkie

src/Adafruit_MCP23XXX.cpp

@@ -235,7 +235,7 @@ uint8_t Adafruit_MCP23XXX::getLastInterruptPin() {
   // clear if found
   if (intpin != 255) {
     Adafruit_BusIO_Register INTCAP(i2c_dev, spi_dev, MCP23XXX_SPIREG,
-                                   getRegister(MCP23XXX_INTCAP));
+                                   getRegister(MCP23XXX_INTCAP, MCP_PORT(intpin)));
     INTCAP.read();
   }