arm: pia-am335x-em: add pinmux for used UARTs

- already set in u-boot, but make sure pins are defined correctly

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: add support for S0 input

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: add support for USB OSC inputs

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: add support for gsm module control IOs

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: add support for EMMC reset signal

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: fix default state of gsm module control pins

- PWRKEY and EMERG_OFF use a reverse logic

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: am33xx: add missing UART signal names

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: fix gpio mux signal name typos

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: add init functions for WL12xx module

- module is not activated yet

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: enable WL12xx module

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: change PHY address for IP175L switch

- MDIO interface provides access to all phys on the switch, 0..3 are the
  external ports, 5 is the switches MII0 interface connected with the CPU.
- Basic networking works with any PHY address 0..5, although configuration
  of the port is only possible when using the correct PHY address 5.

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: enable BT

- we also need to put the EMMC_RESET signal low to enable the output
  of the 1.8V level shifter for the WL12xx UART lines

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