efabless io modules doesn't have a guard for USE_POWER_PINS

[M0stafaRady]

some of _ef_ modules under sky130_fd_io.v don't consider the case of simulating without USE_POWER_PINS.

[M0stafaRady]

modules like:

• sky130_ef_io__vddio_hvc_clamped_pad
• sky130_ef_io__vddio_hvc_clamped_pad
• sky130_ef_io__vdda_hvc_clamped_pad
• sky130_ef_io__vssa_hvc_clamped_pad
• sky130_ef_io__vccd_lvc_clamped_pad
• sky130_ef_io__vssd_lvc_clamped_pad
• sky130_ef_io__top_power_hvc.

not sure if these are all the modules with ports issue when USE_POWER_PINS isn't defined

[RTimothyEdwards]

Shouldn't be too hard to do. Create a pull request.