ANDROID: mm: page_pinner: ensure do_div() arguments matches with respect to type

Fixes the following compiler warnings:

  mm/page_pinner.c:240:28: error: comparison of distinct pointer types
      ('typeof ((ts_usec)) *' (aka 'long long *') and 'uint64_t *'
      (aka 'unsigned long long *')) [-Werror,-Wcompare-distinct-pointer-types]
                unsigned long rem_usec = do_div(ts_usec, 1000000);
                                         ^~~~~~~~~~~~~~~~~~~~~~~~
  include/asm-generic/div64.h:226:28: note: expanded from macro 'do_div'
        (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
               ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~
  mm/page_pinner.c:312:13: error: comparison of distinct pointer types
      ('typeof ((ts_usec)) *' (aka 'long long *') and 'uint64_t *'
      (aka 'unsigned long long *')) [-Werror,-Wcompare-distinct-pointer-types]
        rem_usec = do_div(ts_usec, 1000000);
                   ^~~~~~~~~~~~~~~~~~~~~~~~
  include/asm-generic/div64.h:226:28: note: expanded from macro 'do_div'
        (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
               ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~

Bug: 261962742
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I63bc6e2d82bfd757c4bf9df53a1a17a1a6235ba7