Audio Effects are not processing first buffer

Current implementation in AudioFlinger set the effects to state IDLE
when they are created. Later on when the effect is enabled by the
client, the state changes to STARTING.

Then when the audio playback starts, the AudioFlinger thread loop
calls EffectChain::process_l() to perform the effects processing.
However this method will first call process() and then updateState(),
so the firstprocess won't do anything because the effect is in
STARTING state. After the call to updateState, the state is moved
to ACTIVE and then next calls to process_l() will work as expected.

Change-Id: I9dfd3d5a0e53403034eb42f9366e1b3cdc5249c0