efi_loader: Add console handle references to in/out/err

We register the console in/out protocol on the loaded image handle, but
never tell anyone about it in the systab.

Because of this Shell.efi can not find the input protocol. So let's add
a proper reference.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>