net: vertexcom: mse102x: Return code for mse102x_rx_pkt_spi

The MSE102x doesn't provide any interrupt register, so the only way
to handle the level interrupt is to fetch the whole packet from
the MSE102x internal buffer via SPI. So in cases the interrupt
handler fails to do this, it should return IRQ_NONE. This allows
the core to disable the interrupt in case the issue persists
and prevent an interrupt storm.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://patch.msgid.link/20250509120435.43646-6-wahrenst@gmx.net


Signed-off-by: Jakub Kicinski <kuba@kernel.org>