doc: fatinfo man-page

Provide a man-page for the fatinfo command.

The .rst file was lost in patch 15d9694600 ("doc: fatinfo man-page").

Fixes: 15d9694600 ("doc: fatinfo man-page")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

doc/usage/fatinfo.rst

@@ -0,0 +1,51 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+fatinfo command
+===============
+
+Synopsis
+--------
+
+::
+
+    fatinfo <interface> <dev[:part]>
+
+Description
+-----------
+
+The fatinfo command displays information about a FAT partition.
+
+interface
+    interface for accessing the block device (mmc, sata, scsi, usb, ....)
+
+dev
+    device number
+
+part
+    partition number, defaults to 1
+
+Example
+-------
+
+Here is the output for a partition on a 32 GB SD-Card:
+
+::
+
+    => fatinfo mmc 0:1
+    Interface:  MMC
+      Device 0: Vendor: Man 00001b Snr 97560602 Rev: 13.8 Prod: EB1QT0
+                Type: Removable Hard Disk
+                Capacity: 30528.0 MB = 29.8 GB (62521344 x 512)
+    Filesystem: FAT32 "MYDISK     "
+    =>
+
+Configuration
+-------------
+
+The fatinfo command is only available if CONFIG_CMD_FAT=y.
+
+Return value
+------------
+
+The return value $? is set to 0 (true) if the partition is a FAT partition.
+Otherwise it is set to 1 (false).