soc: mediatek: pwrap: Use readx_poll_timeout() instead of custom function

Function pwrap_wait_for_state() is a function that polls an address
through a helper function, but this is the very same operation that
the readx_poll_timeout macro means to do.
Convert all instances of calling pwrap_wait_for_state() to instead
use the read_poll_timeout macro.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220517104712.24579-2-angelogioacchino.delregno@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>