[media] DocBook: better organize the function descriptions for frontend

[media] DocBook: better organize the function descriptions for frontend

Move the function ioctl definitions to the end of the chapter,
at their importance. That makes the document better organized,
as the DVB frontend system call index will look like:

	open()
	close()
	ioctl FE_GET_INFO — Query DVB frontend capabilities and returns information about the front-end. This call only requires read-only access to the device
	ioctl FE_READ_STATUS — Returns status information about the front-end. This call only requires read-only access to the device
	ioctl FE_SET_PROPERTY, FE_GET_PROPERTY — FE_SET_PROPERTY sets one or more frontend properties. FE_GET_PROPERTY returns one or more frontend properties.
	ioctl FE_DISEQC_RESET_OVERLOAD — Restores the power to the antenna subsystem, if it was powered off due to power overload.
	ioctl FE_DISEQC_SEND_MASTER_CMD — Sends a DiSEqC command
	ioctl FE_DISEQC_RECV_SLAVE_REPLY — Receives reply from a DiSEqC 2.0 command
	ioctl FE_DISEQC_SEND_BURST — Sends a 22KHz tone burst for 2x1 mini DiSEqC satellite selection.
	ioctl FE_SET_TONE — Sets/resets the generation of the continuous 22kHz tone.
	ioctl FE_SET_VOLTAGE — Allow setting the DC level sent to the antenna subsystem.
	ioctl FE_ENABLE_HIGH_LNB_VOLTAGE — Select output DC level between normal LNBf voltages or higher LNBf voltages.
	ioctl FE_SET_FRONTEND_TUNE_MODE — Allow setting tuner mode flags to the frontend.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>