drivers: media: radio: si4709: update power management

<4>[    4.722171] i2c-core: driver [Si4709] using legacy suspend method
<4>[    4.722351] i2c-core: driver [Si4709] using legacy resume method

Signed-off-by: Humberto Borba <humberos@gmail.com>
Change-Id: I5e4a92bed7bb53f351985b9ef6c97ff7967e6de3