ANDROID: binder: fix KMI-break due to address type change

In commit ("binder: keep vma addresses type as unsigned long") the vma
address type in 'struct binder_alloc' and 'struct binder_buffer' is
changed from 'void __user *' to 'unsigned long'.

This triggers the following KMI issues:

  type 'struct binder_buffer' changed
    member changed from 'void* user_data' to 'unsigned long user_data'
      type changed from 'void*' to 'unsigned long'

  type 'struct binder_alloc' changed
    member changed from 'void* buffer' to 'unsigned long buffer'
      type changed from 'void*' to 'unsigned long'

This offending commit is being backported as part of a larger patchset
from upstream in [1]. Lets fix these issues by doing a partial revert
that restores the original types and casts to an integer type where
necessary.

Note this approach is preferred over dropping the single KMI-breaking
patch from the backport, as this would have created non-trivial merge
conflicts in the subsequent cherry-picks.

Bug: 254650075
Link: https://lore.kernel.org/all/20231201172212.1813387-1-cmllamas@google.com/

 [1]
Change-Id: Ief9de717d0f34642f5954ffa2e306075a5b4e02e
Signed-off-by: Carlos Llamas <cmllamas@google.com>