wlcore: sdio: allow pm to handle sdio power

pm_runtime handles sdio power on and power off transitions.
An old workaround for trying to control the power explicitly from the
driver was in fact causing failures on suspend/resume as the mmc layer
already power the module on resume.

In case of resume pm_runtime_get sync returns a positive device's usage
count causing the driver to try an re-initialize an already initialized
device. This was causing sdio bus failure on resume.

Remove this manual power on/off sequence as it is in-fact not needed.

Signed-off-by: Eyal Reizer <eyalr@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>