uboot-phytec

i.mx6ul: xpress: update UART init for current board revision

UART pinmux has been changed on the last board revision. Change
board pinmux accordingly. Console is on UART7 now, add pinmux,
base address and update console string in environment.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Stefano Babic <sbabic@denx.de>