[media] libv4l-introduction.rst: improve crossr-references

Use C cross-references to mention the V4L2 API calls on all
places it occurs inside this file.

While here, also mark constants as such.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2016-09-08 06:21:01 -03:00
commit e452134cee