Input: spear-keyboard - provide thaw and poweroff routines

Thaw and poweroff routines are missing for spear-keyboard. They are
required for:
- Error case scenarios during freeze
- Using test features, of hibernate.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>