If the device does not come straight from reset, we might receive an IRQ
before we are ready to handle it.
Fixes:
[ 0.832328] Unable to handle kernel read from unreadable memory at virtual address 0000000000000010
[ 1.040343] Call trace:
[ 1.040347] mtk_spi_can_dma+0xc/0x40
...
[ 1.262265] start_kernel+0x338/0x42c
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>