Bluetooth: Remove redundant read_host_features commands

Previously the write_le_enable would trigger a read_host_features
command but since we have access to the value LE support was set to we
can simply just clear or set the bit in hdev->host_features. This also
removes a second unnecessary read_host_features command from the device
initialization procedure since LE is only enabled after the first
read_host_features command completes.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>