va-macro: Add autosuspend after pm_runtime_get_sync

If va_macro_tx_va_mclk_enable returns error,
va macro autosuspend will not be called.
Add autosuspend before return.

Change-Id: Iea3728fab2d240514ca4a7e02ef535edce977ee8
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>