regmap: Avoid namespace collision within macro & tidy up

Renamed variable "timeout" to "__timeout" & "pollret" to "__ret" to
avoid namespace collision. Tidy up macro arguments with parentheses.

Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>