greybus: hid: hid should not be part of the bridged-phy driver.

HID is a stand-alone greybus protocol, not part of the bridged-phy
protocols, so make it a stand-alone kernel module.

Note, some hard-coded android init script might need to be changed to
load the gb-hid.ko kernel module now.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>