SPRacingH7EF - Initial target support.

[hydra]

Initial support for the SPRacingH7EF.

This FC was made a couple of years ago, this is a PR to finally add the target for it.

Notable features:

• Dual ICM42688P gyro, with 2xFSYNC/CLKIN and 2xINT connected to TIM8 CH1-4, for those wanting to experiment with gyro clock generation.
• OctoSPI flash (using IO lines 4-7, not 0-3).
• SPI flash.

Notes:

• The target uses memory mapped flash to run the code from, however BF is unaware of this and ignores the fact that OctoSPI is even in use.
• Since BF is unaware of OctoSPI flash, it uses the SPI flash for config storage and blackbox logging.

Requires betaflight/betaflight#13605 (4.5-maintenance) / betaflight/betaflight#13604 (master)