fusee: Complete re-write of the hardware initialization code: ...

- Updated code to match hekate's;
- Improved nxboot (now boots firmwares 2.x successfully);
- Temporarily disabled built-in boot system module support;
- Fixed multiple bugs.

Fix multiple issues reported by Coverity Scan

fusee: Disable the SDCLK when switching to low voltage.

fusee: Fix SDMMC high speed support and other bugs.

Fusee: Deployed new SDMMC driver in fusee-secondary. All stages boot now. ...

Fusee: Fixed wrong argument in se.c function.
Fusee: Improved timers.

fusee: Correct wrong comment (thanks @desowin)

fusee: SDMMC driver re-design: ...

- Based on hekate's, linux's and u-boot's source code;
- Full support for SD and MMC;
- Fixes multiple issues;
- Deployed first in fusee-primary.

fusee: Code cleanup and style fixes.