[media] doc-rst: improve DTV_BANDWIDTH_HZ notes

There are several notes for this DTV property. Some are
outdated, so take some care of it, making it updated.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/dvb/fe_property_parameters.rst

@@ -219,23 +219,29 @@ Bandwidth for the channel, in HZ.
 Possible values: ``1712000``, ``5000000``, ``6000000``, ``7000000``,
 ``8000000``, ``10000000``.
 
-Notes:
+.. note::
+
+  #. DVB-T supports 6, 7 and 8MHz.
+
+  #. DVB-T2 supports 1.172, 5, 6, 7, 8 and 10MHz.
 
-1) For ISDB-T it should be always 6000000Hz (6MHz)
+  #. ISDB-T supports 5MHz, 6MHz, 7MHz and 8MHz, although most
+     places use 6MHz.
 
-2) For ISDB-Tsb it can vary depending on the number of connected
-segments
+  #. On DVB-C and DVB-S/S2, the bandwidth depends on the symbol rate.
+     So, the Kernel will silently ignore setting :ref:`DTV-BANDWIDTH-HZ`.
 
-3) Bandwidth doesn't apply for DVB-C transmissions, as the bandwidth for
-DVB-C depends on the symbol rate
+  #. For DVB-C and DVB-S/S2, the Kernel will return an estimation of the
+     bandwidth, calculated from :ref:`DTV-SYMBOL-RATE` and from
+     the rolloff, with is fixed for DVB-C and DVB-S.
 
-4) Bandwidth in ISDB-T is fixed (6MHz) or can be easily derived from
-other parameters (DTV_ISDBT_SB_SEGMENT_IDX,
-DTV_ISDBT_SB_SEGMENT_COUNT).
+  #. For DVB-S2, the bandwidth estimation will use :ref:`DTV-ROLLOFF`.
 
-5) DVB-T supports 6, 7 and 8MHz.
+  #. For ISDB-Tsb, it can vary depending on the number of connected
+     segments.
 
-6) In addition, DVB-T2 supports 1.172, 5 and 10MHz.
+  #. Bandwidth in ISDB-Tsb can be easily derived from other parameters
+     (DTV_ISDBT_SB_SEGMENT_IDX, DTV_ISDBT_SB_SEGMENT_COUNT).
 
 
 .. _DTV-INVERSION: