drivers: usb_device: smartbond: Fix EP OUT after resume

When device was resumed from sleep OUT endpoints were most
likely not enabled due to condition that checked pending transfer.
Configured OUT endpoints should be enabled (ready for RX)
if they were enabled by interfaces.

Now separate bit field enabled is added and check to
see if OUT endpoint should be ready for reception after
sleep is done.

Signed-off-by: Jerzy Kasenberg <jerzy.kasenberg@codecoup.pl>