ARM: 9041/1: sti LL_UART: add STiH418 SBC UART0 support

Add the entry for the STiH418 SBC UART0 low level uart.

Signed-off-by: Alain Volmat <avolmat@me.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>