OMAP tags are deprecrated so drop them.

Drop UART config data which decides which UARTs to enable during boot.
This is no longer necessary since serial core code disables clocks
after inactivity.

Background: with new UART idle code, all on-chip UARTs are idled using
a configurable inactivity timer (default 5 seconds.)  After the
inactivity timer, UART clocks are disabled automatically.
Signed-off-by: NKalle Valo <kalle.valo@iki.fi>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>