can: mcp251x: Use dev_name() during request_threaded_irq()

Passing driver name as name during request_threaded_irq() results in all
CAN IRQs have same name. This does not help much to easily identify which
IRQ belongs to which CAN instance. Therefore pass dev_name() during
request_threaded_irq() so that better identifiable name is listed for
CAN devices in cat /proc/interrupts output.

Output of cat /proc/interrupts
Before this patch:
  253:          2  gpio-mxc  13 Edge      mcp251x
  259:          2  gpio-mxc  19 Edge      mcp251x
After this patch:
  253:          2  gpio-mxc  13 Edge      spi1.1
  259:          2  gpio-mxc  19 Edge      spi1.2

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>