ARM: OMAP2+: UART: remove unused fields in omap_uart_state.

commit 2fd149645eb46d261 (ARM: OMAP2+: UART: Remove
omap_uart_can_sleep and add pm_qos) removed the last usage of
'can_sleep' but did not remove the field.

commit 8612bd22f3036974 (ARM: OMAP2+: UART: Avoid console uart idling
during bootup) removed the last non-trivial use of 'pdev'.

So remove these fields and the one trivial use.

Acked-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: NeilBrown <neilb@suse.de>
[khilman@ti.com: minor changelog edits]
Signed-off-by: Kevin Hilman <khilman@ti.com>