lib/fatfs: Allow a smaller minimum sector count for fatfs to be created.

lib/fatfs/ff.c

@@ -4073,7 +4073,7 @@ FRESULT f_mkfs (
 		n_vol = LD_DWORD(tbl+12);	/* Volume size */
 	} else {
 		/* Create a partition in this function */
-		if (disk_ioctl(pdrv, GET_SECTOR_COUNT, &n_vol) != RES_OK || n_vol < 128)
+		if (disk_ioctl(pdrv, GET_SECTOR_COUNT, &n_vol) != RES_OK || n_vol < 48) /* dpgeorge: allow smaller minimum volume; 48 was 128 */
 			return FR_DISK_ERR;
 		b_vol = (sfd) ? 0 : 63;		/* Volume start sector */
 		n_vol -= b_vol;				/* Volume size */