[media] docs-rst: convert uAPI structs to C domain

instead of declaring the uAPI structs using usual refs, e. g.:
	.. _foo-struct:

Use the C domain way:
	.. c:type:: foo_struct

This way, the kAPI documentation can use cross-references to
point to the uAPI symbols.

That solves about ~100 undefined warnings like:
	WARNING: c:type reference target not found: foo_struct

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/cec/cec-ioc-adap-g-caps.rst

@@ -36,12 +36,12 @@ Description
 
 All cec devices must support :ref:`ioctl CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`. To query
 device information, applications call the ioctl with a pointer to a
-struct :ref:`cec_caps <cec-caps>`. The driver fills the structure and
+struct :c:type:`cec_caps`. The driver fills the structure and
 returns the information to the application. The ioctl never fails.
 
 .. tabularcolumns:: |p{1.2cm}|p{2.5cm}|p{13.8cm}|
 
-.. _cec-caps:
+.. c:type:: cec_caps
 
 .. flat-table:: struct cec_caps
     :header-rows:  0

Documentation/media/uapi/cec/cec-ioc-adap-g-log-addrs.rst

@@ -68,7 +68,7 @@ logical address types are already defined will return with error ``EBUSY``.
 
 .. tabularcolumns:: |p{1.0cm}|p{7.5cm}|p{8.0cm}|
 
-.. _cec-log-addrs:
+.. c:type:: cec_log_addrs
 
 .. cssclass:: longtable
 

Documentation/media/uapi/cec/cec-ioc-dqevent.rst

@@ -105,7 +105,7 @@ it is guaranteed that the state did change in between the two events.
 
 .. tabularcolumns:: |p{1.0cm}|p{4.2cm}|p{2.5cm}|p{8.8cm}|
 
-.. _cec-event:
+.. c:type:: cec_event
 
 .. flat-table:: struct cec_event
     :header-rows:  0

Documentation/media/uapi/cec/cec-ioc-receive.rst

@@ -76,7 +76,7 @@ result.
 
 .. tabularcolumns:: |p{1.0cm}|p{3.5cm}|p{13.0cm}|
 
-.. _cec-msg:
+.. c:type:: cec_msg
 
 .. cssclass:: longtable