fs: correct comments for fs_read() and write()

The existing comments where confusing read and write. The comment for
fs_write() had:
"@addr: The address to read into"

So let's rework the comments and format them in Sphinx style.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/include/fs.h b/include/fs.h
index 6854597..7601b03 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -71,30 +71,33 @@
  */
 int fs_size(const char *filename, loff_t *size);
 
-/*
- * fs_read - Read file from the partition previously set by fs_set_blk_dev()
- * Note that not all filesystem types support either/both offset!=0 or len!=0.
+/**
+ * fs_read() - read file from the partition previously set by fs_set_blk_dev()
  *
- * @filename: Name of file to read from
- * @addr: The address to read into
- * @offset: The offset in file to read from
- * @len: The number of bytes to read. Maybe 0 to read entire file
- * @actread: Returns the actual number of bytes read
- * @return 0 if ok with valid *actread, -1 on error conditions
+ * Note that not all filesystem drivers support either or both of offset != 0
+ * and len != 0.
+ *
+ * @filename:	full path of the file to read from
+ * @addr:	address of the buffer to write to
+ * @offset:	offset in the file from where to start reading
+ * @len:	the number of bytes to read. Use 0 to read entire file.
+ * @actread:	returns the actual number of bytes read
+ * Return:	0 if OK with valid *actread, -1 on error conditions
  */
 int fs_read(const char *filename, ulong addr, loff_t offset, loff_t len,
 	    loff_t *actread);
 
-/*
- * fs_write - Write file to the partition previously set by fs_set_blk_dev()
- * Note that not all filesystem types support offset!=0.
+/**
+ * fs_write() - write file to the partition previously set by fs_set_blk_dev()
+ *
+ * Note that not all filesystem drivers support offset != 0.
  *
- * @filename: Name of file to read from
- * @addr: The address to read into
- * @offset: The offset in file to read from. Maybe 0 to write to start of file
- * @len: The number of bytes to write
- * @actwrite: Returns the actual number of bytes written
- * @return 0 if ok with valid *actwrite, -1 on error conditions
+ * @filename:	full path of the file to write to
+ * @addr:	address of the buffer to read from
+ * @offset:	offset in the file from where to start writing
+ * @len:	the number of bytes to write
+ * @actwrite:	returns the actual number of bytes written
+ * Return:	0 if OK with valid *actwrite, -1 on error conditions
  */
 int fs_write(const char *filename, ulong addr, loff_t offset, loff_t len,
 	     loff_t *actwrite);