net: vertexcom: mse102x: Fix possible stuck of SPI interrupt

The MSE102x doesn't provide any SPI commands for interrupt handling.
So in case the interrupt fired before the driver requests the IRQ,
the interrupt will never fire again. In order to fix this always poll
for pending packets after opening the interface.

Fixes: 2f207cbf ("net: vertexcom: Add MSE102x SPI support")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250430133043.7722-2-wahrenst@gmx.net


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