regulator: max77503: remove unused struct 'max77503_dev'

'max77503_dev' is unused since the original
commit a0c543bd ("regulator: max77503: Add ADI MAX77503 support").

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://msgid.link/r/20240528174659.53022-1-linux@treblig.org


Signed-off-by: Mark Brown <broonie@kernel.org>