drop irq id and rebase instead of of offset

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

this will also fix the clock support as we now switch to allocated generic
device

as we can need to associate the clock and the device but the driver is probe
before the association

we also change the atmel serial name to "atmel_usart" to simplify sharing with
linux

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

AT91sam9261 series is an ARM 926ej-s SOC family clocked at 190/100MHz.

The first board that embeds at91sam9261 chip is the AT91SAM9261-EK.
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3820

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>