ARM: LPC32xx: High Speed UART configuration via DT

This patch fixes the DTS files for the High Speed UARTs 1, 2 and 7 of the
LPC32xx SoC, adjusting the compatible strings, adding interrupts and status
configuration. On the PHY3250 reference board, UART2 is enabled.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>