regulator: pwm-regulator: Don't assign structure attributes right away

Perhaps this is just personal preference, but ...

This patch introduces a new local variable to receive and test regulator
initialisation data.  It simplifies and cleans up the code making it
that little bit easier to read and maintain.  The local value is assigned
to the structure attribute when all the others are.  This is the way we
usually do things.

Prevents this kind of nonsense:

	this->is->just.silly = fetch_silly_value(&pointer);
	if (!this->is->just.silly) {
		printk("Silly value failed: %d\n", this->is->just.silly);
		return this->is->just.silly;
	}

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>