docs: hwmon: tmp103.rst: fix bad usage of UTF-8 chars

While UTF-8 characters can be used at the Linux documentation,
the best is to use them only when ASCII doesn't offer a good replacement.
So, replace the occurences of the following UTF-8 characters:

	- U+2013 ('–'): EN DASH

In this specific case, EN DASH was used instead of a minus
sign. So, replace it by a single hyphen.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/73b3c7c1eef5c12ddc941624d23689313bd56529.1620744606.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>