media: ipu3.rst: Format media-ctl and yavta commands as code blocks

Fix improper line breaks and format all example yavta and media-ctl
commands as code blocks to improve readability.

Signed-off-by: Jordan Hand <jorhand@linux.microsoft.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>