ENGR00137979-1 add performance monitor driver

ENGR00137979-1 add performance monitor driver

	add performance monitor driver.
	sample:
		cd /sys/devices/platform/mxs-perfmon.0/
   		'echo 1 > MIDn-xxx' to enable monitor this channel
			n: channel number; xxx: name of channel (PXP, LCD...)
			you can enable the multiple channels you want to
			monitor respectively using this command.
			use following command to check the channel is enabled
		'cat MIDn-xxx'
			1: enable; 0: disable

		'echo read > Monitor' to monitor all read activities
		'echo start > Monitor' to start monitoring
		'echo fetch > Monitor' to get a snapshot of monitor statistics.
		'cat xxx_Count' to show the statistics.
			xxx: name of statistics, (Data, Transfer, Latency...)

		'echo clear > Monitor' to clear snapshot of monitor statistics.
		'echo stop > Monitor' to stop monitoring

Signed-off-by: Tony Lin <tony.lin@freescale.com>