docs: driver-api: ioctl.rst: replace some characters

docs: driver-api: ioctl.rst: replace some characters

The conversion tools used during DocBook/LaTeX/html/Markdown->ReST
conversion and some cut-and-pasted text contain some characters that
aren't easily reachable on standard keyboards and/or could cause
troubles when parsed by the documentation build system.

Replace the occurences of the following characters:

	- U+00a0 (' '): NO-BREAK SPACE
	  as it can cause lines being truncated on PDF output

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/b2186e313f990488ded56d9b8d35a2d1fe479aa1.1623826294.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>