imx: ventana: remove dependence on EECONFIG_SATA eeprom feature bit

imx: ventana: remove dependence on EECONFIG_SATA eeprom feature bit

The MSATA feature is a board-specific feature on Gateworks Ventana boards.

In most cases a 2:1 mux will steer either PCIe or SATA to a miniPCIe socket
through an MSATA_EN gpio. In these such cases assign the gpio in the board
specific struct and use its presence to determine if we default the GPIO to
PCIe and if we later steer it according to hwconfig.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>