pass: gov: Add new GOV_HOTPLUG_ONLY definition

pass: gov: Add new GOV_HOTPLUG_ONLY definition

This patch adds the new GOV_HOTPLUG_ONLY definition which uses
the hotplug interface for h/w resource such as CPU without
the runtime governors such as GOV_RADIATION, GOV_STEP.

- Detailed description of the PASS governor
: The PASS governor contains both the hotplug and runtime governor
for each resource
------------------------------------------------------------------
Governor name    | Hotplug interface | PASS Runtime governor     |
------------------------------------------------------------------
GOV_DUMMY        | Un-used           | Un-used                   |
GOV_HOTPLUG_ONLY | Used              | Un-used                   |
GOV_RADIATION    | Used              | Used (Radiation governor) |
GOV_STEP         | Used              | Used (Step governor)      |
------------------------------------------------------------------

For example,
- GOV_DUMMY        for TM1/TM2's BUS/GPU resource
- GOV_HOTPLUG_ONLY for TM1's CPU resource
- GOV_RADIATION    for TM2's big.LITTLE CPU resource
- GOV_STEP         for TM2's big.LITTLE CPU resource

Change-Id: Id8caebcf32f00a19dbf63192a6d952384df21bf7
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>