oak: set a debounce time for suspend signal
oak: set a debounce time for suspend signal

The suspend signal from SoC of oak  should be kept at least 50ms.
Add a debounce time for suspend singal detection, to avoid transient
state during SoC boot up.

BUG=chrome-os-partner:42023
BRANCH=none
TEST=plug PD power adaptor to type-c port C1,
     The keyboard should be worked (Ensure EC communication is oaky)

Change-Id: I4a6bb4e8ba9d417fe2a3045846d38b2129516d78
Signed-off-by: Ben Lok <310171a828df105188e0b545d65d6370e8133283@mediatek.com>
Reviewed-on: https://chromium-review.googlesource.com/282471
Reviewed-by: Rong Chang <3a05493f7adfb36d203f663b3bc2ba30e9d6284f@chromium.org>
Commit-Queue: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

fourier49/BIZ_EC,fourier49/BZ_DEV_EC,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,coreboot/chrome-ec,fourier49/BIZ_EC,fourier49/BZ_DEV_EC,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,fourier49/BIZ_EC,fourier49/BZ_DEV_EC,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BIZ_EC,fourier49/BZ_DEV_EC,md5555/ec,coreboot/chrome-ec,md5555/ec,md5555/ec,coreboot/chrome-ec