ARM: OMAP2+: UART: Avoid console uart idling during bootup

ARM: OMAP2+: UART: Avoid console uart idling during bootup

Omap-uart can be used as console uart to print early boot messages using
earlyprintk so for console uart prevent hwmod reset or idling during bootup.

Identify omap-uart used as console and avoid idling rather than preventing
all omap-uarts from idling during bootup. Update the comments for the same.

Remove the uart idling and enabling back using hwmod_idle/omap_device_enable
for all uarts that where left enabled from boot to set the hwmod framework
state machine right. This need not be taken care any more serial.c rather
can be handled within the hwmod framework.
Reference: http://www.spinics.net/lists/linux-omap/msg60300.html

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>