net: mv643xx: use devm_platform_ioremap_resource

This combines multiple steps in one function.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20240930202951.297737-2-rosenp@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>