fatfs: Allow storing more mode flags in a dir entry

[OlliV]

Bits 0, 1, 2, 5, 6, and 7 of DIR_NTRes (0x0c) are not commonly used by any modern OS and thus those could be utilized for adding more mode bits:

• 0: S_IRUSR
• 1: S_IRGRP
• 2: S_IWGRP
• 5: S_IXGRP
• 6: S_IROTH
• 7: S_IWOTH

x and s bits are not very important in Zeke so those don't necessarily need support or they could be mapped elsewhere.