ARM: versatile: pass console setting to the kernel

The Versatiles come up with the primary UART set to ttyAMA0 at
38400 baud, and unless we pass this to the kernel it will assume
it is set to 9600 baud which will be quite awkward for the
terminal, let's try to be helpful and inform the kernel what
setting is used.

Cc: Stefano Babic <sbabic@denx.de>
Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>