ARM: OMAP2+: UART: cleanup 8250 console driver support

We had been using traditional 8250 driver as uart console driver
prior to omap-serial driver. Since we have omap-serial driver
in mainline kernel for some time now it has been used as default
uart console driver on omap2+ platforms. Remove 8250 support for
omap-uarts.

Serial_in and serial_out override for 8250 serial driver is also
removed. Empty fifo read fix is already taken care with omap-serial
driver with data ready bit check from LSR reg before reading RX fifo.
Also waiting for THRE(transmit hold reg empty) is done with wait_for_xmitr
in omap-serial driver.

Serial_in/out overrides are not neceesary for omap-serial driver
and things that are taken with omap-serial driver are removed here.

Remove headers that were necessary to support 8250 support
and remove all config bindings done to keep 8250 backward compatibility
while adding omap-serial driver. Remove omap_uart_reset needed for
8250 autoconf.

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