ANDROID: KVM: arm64: Add function to topup allocator with flags

The SMMUv3 driver might be called from an atomic context, which
requires to pass GFP_ATOMIC to the allocation function.
Add an extra function that accepts gfp flags that the driver can use.

Bug: 367702966
Bug: 277989609
Bug: 278749606

Change-Id: I99ed309d46a00d662e972e54ac63c5c96382d959
Signed-off-by: Mostafa Saleh <smostafa@google.com>