select_interrupt_line_1 on stm32g4 selects wrong interrupts

[projectgus]

The current implementation of select_interrupt_line_1 copies the Interrupts bitflags directly to the FDCAN_ILS register. This works on STM32H7 because this register's bits have the same mapping as other interrupt registers like FDCAN_IE.

On STM32G4 the bits are groups of interrupts, instead:

So currently this results in unpredictable interrupt-to-line mappings.

[projectgus]

I might have time to submit a fix for this, my only question is whether the public interface needs to be the same across both families of chips. If it can be a different function signature for G4/etc then it seems relatively straightforward.

If they need to be compatible then maybe not, although a G4 compatible function could be implemented to work on H7 (it would just be less flexible).