FATFS enable support for multiple drives
Current implementation has drive numbers and paths hardcoded to support
only one FATFS drive. Arduino has it's own SPI driver to allow
compatibility and flexibility. With the MR it is possible to have up to
```_VOLUMES``` drives connected (SPI, SDMMC and others) at the same
time and accessed through VFS
See merge request !478
Current implementation has drive numbers and paths hardcoded to support
only one FATFS drive. Arduino has it's own SPI driver to allow
compatibility and flexibility. With the MR it is possible to have up to
```_VOLUMES``` drives connected (SPI, SDMMC and others) at the same
time and accessed through VFS