am335x-bone: add wilink8 support

* enable mmc2 used for wlan and uart4 used for bluetooth
* Disables emmc on boneblack as it is using the same mmc(2)
* configure the gpios used for wlan and bluetooth controls
* add fixed voltage regulator used for wlan power control
* Configure shared transport support for uart4

Signed-off-by: Eyal Reizer <eyalr@ti.com>
[made to apply to 3.14]
Signed-off-by: Radek Dostal <radek.dostal@streamunlimited.com>
wlcore/wl18xx: handle rc updates in a separate work

sta_rc_update runs in atomic context. thus, a new work
should be scheduled in order to configure the fw
with the required configuration.

Signed-off-by: Eliad Peller <eliad@wizery.com>
wlcore: always set MMC_PM_KEEP_POWER (workaround)

Due to some mmc layer issues, the system automatically
powers us up on resume, which later cause issues when
we try to restore_power again explicitly.

temporarily workaround it by always asking to keep power.
this is fine as driver controls the chip power anyway.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Ido Yariv <ido@wizery.com>
am335x-bone: switch to using level interrupts for wl8

in newer kerenls, we seem to miss interrupts when working with
edge irqs, so revert back to level irqs.

Signed-off-by: Eyal Reizer <eyalr@ti.com>