MAINTAINERS: Add reviewer entry for microchip mcp25xxfd SPI-CAN network driver

This patch adds Thomas Kopp as a reviewer for the mcp25xxfd CAN driver.
Signed-off-by: Thomas Kopp <thomas.kopp@microchip.com>
Link: https://lore.kernel.org/r/20200916101334.1277-1-thomas.kopp@microchip.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

MAINTAINERS

@@ -10674,6 +10674,7 @@ F:	drivers/hid/hid-mcp2221.c
 MCP25XXFD SPI-CAN NETWORK DRIVER
 M:	Marc Kleine-Budde <mkl@pengutronix.de>
 M:	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+R:	Thomas Kopp <thomas.kopp@microchip.com>
 L:	linux-can@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/net/can/microchip,mcp25xxfd.yaml