[PATCH] powerpc/pseries/svm: Make mem_encrypt.h self contained

[Tian, Kevin]

> From: Jason Gunthorpe <jgg at nvidia.com>
> Sent: Thursday, November 20, 2025 11:07 PM
> 
> Add the missing forward declarations and includes so it does not have
> implicit dependencies. mem_encrypt.h is a public header imported by
> drivers. Users should not have to guess what include files are needed.
> 
> Resolves a kbuild splat:
> 
>    In file included from drivers/iommu/generic_pt/fmt/iommu_amdv1.c:15:
>    In file included from drivers/iommu/generic_pt/fmt/iommu_template.h:36:
>    In file included from drivers/iommu/generic_pt/fmt/amdv1.h:23:
>    In file included from include/linux/mem_encrypt.h:17:
> >> arch/powerpc/include/asm/mem_encrypt.h:13:49: warning: declaration
> of 'struct device' will not be visible outside of this function [-Wvisibility]
>       13 | static inline bool force_dma_unencrypted(struct device *dev)
> 
> Fixes: 879ced2bab1b ("iommupt: Add the AMD IOMMU v1 page table
> format")
> Reported-by: kernel test robot <lkp at intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202511161358.rS5pSb3U-
> lkp at intel.com/
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>