BACKPORT: FROMLIST: KVM: arm64: Add function to topup generic allocator

Soon, IOMMU driver might need to topup the IOMMU pool from map_pages
IOMMU operation, which has a gfp flag is it might be called from
atomic context, add a function to topup an allocator with an ID
that also accepts gfp flags.

Link: https://lore.kernel.org/all/20241212180423.1578358-47-smostafa@google.com/



Bug: 357781595
Bug: 384432312

Change-Id: I9bb0522a1baa92fdaf81b1e5ad92c6477e9a5954
Signed-off-by: Mostafa Saleh <smostafa@google.com>