Header hardware targets depend on hardware_claim_headers

[ooxi]

A target created by pico_simple_hardware_headers_target must depend on hardware_claim_headers not hardware_claim.

This avoids adding claim.c to the user sources. If the user wanted claim.c to be added to the sources, the user would have used the targed defined by pico_simple_hardware_impl_target.

This is not an issue for hardware_structs since this target does not define sources.

Fixes #957

[kilograham]

presumably you should now also add hardware_claim as a dependency during pico_simple_hardware_impl_target

[ooxi]

@kilograham thanks for the feedback, I will update the patch accordingly

[ooxi]

@kilograham I have updated the patch accordingly and tested the change in my application

[kilograham]

closed in favor of #1211