fs: inode.c: get rid of docs warnings

Use *foo makes the toolchain to think that this is an emphasis, causing
those warnings:

	./fs/inode.c:1609: WARNING: Inline emphasis start-string without end-string.
	./fs/inode.c:1609: WARNING: Inline emphasis start-string without end-string.
	./fs/inode.c:1615: WARNING: Inline emphasis start-string without end-string.

So, use, instead, ``*foo``, in order to mark it as a literal block.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/e8da46a0e57f2af6d63a0c53665495075698e28a.1586881715.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

fs/inode.c

@@ -1606,14 +1606,14 @@ EXPORT_SYMBOL(iput);
  *	@inode:  inode owning the block number being requested
  *	@block: pointer containing the block to find
  *
- *	Replaces the value in *block with the block number on the device holding
+ *	Replaces the value in ``*block`` with the block number on the device holding
  *	corresponding to the requested block number in the file.
  *	That is, asked for block 4 of inode 1 the function will replace the
- *	4 in *block, with disk block relative to the disk start that holds that
+ *	4 in ``*block``, with disk block relative to the disk start that holds that
  *	block of the file.
  *
  *	Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a
- *	hole, returns 0 and *block is also set to 0.
+ *	hole, returns 0 and ``*block`` is also set to 0.
  */
 int bmap(struct inode *inode, sector_t *block)
 {