TF700T: fix asusdec keylayout

Since we don't have Asus KeyCodeLabels, asusdec.kl is broken. Map
specific device keys to F1..F7 (all of this keys are handled by the
asusdec library and any of them are passed to apps)

Patchset 2: Fixed keys with WAKE_DROPPED option (to ensure the device is wake
            up on key stroke)

Change-Id: I6e2fd2e601704d7f816c6a9006f80fec44a3de96
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>