spi: omap2-mcspi: allow selection of MOSI line

- OMAP devices allow the configuration of the direction of SPI data lines
- add a setting to switch the default D0 <= MISO, D1 => MOSI

note: a similar patch with dt support is in 3.9

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia335x: fix spi initialization

- we use the new direction switch as our MCP2515 configuration uses
  D0 as MOSI and D1 as MISO
- fix spi bus_num, which start with 1

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: omap2 am33xx: fix clkout2 definition

- clkout2 doesn't support by 8 division of source clock
  error in TRM
- clkout2 source mask includes the lowest 3 bits of its config register

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia335x: change source clock for clkout2

- change to get a 12 MHz clock because 192/8 is not supported

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia335x: enable pullup on input line for first spi bus

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia335x: move clkout2 enable after serial_init

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
pia335x: add default config with support for KM E2 board

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>