provide generic page_to_phys and phys_to_page implementations v3

[Arnd Bergmann]

On Wed, Oct 23, 2024, at 05:36, Christoph Hellwig wrote:
> page_to_phys is duplicated by all architectures, and from some strange
> reason placed in <asm/io.h> where it doesn't fit at all.  
>
> phys_to_page is only provided by a few architectures despite having a lot 
> of open coded users.
>
> Provide generic versions in <asm-generic/memory_model.h> to make these
> helpers more easily usable.
>

I've applied this to the asm-generic tree now.

Thanks for the cleanup!

     Arnd