This fixes a warning shown when phys_addr_t is 32-bit int when compiling
with clang:
  mm/memblock.c:927:15: warning: implicit conversion from 'unsigned long long'
        to 'phys_addr_t' (aka 'unsigned int') changes value from
        
18446744073709551615 to 
4294967295 [-Wconstant-conversion]
                                  r->base : ULLONG_MAX;
                                            ^~~~~~~~~~
  ./include/linux/kernel.h:30:21: note: expanded from macro 'ULLONG_MAX'
  #define ULLONG_MAX      (~0ULL)
                           ^~~~~
Link: http://lkml.kernel.org/r/20180319005645.29051-1-stefan@agner.ch
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
                        r = &type_b->regions[idx_b];
                        r_start = idx_b ? r[-1].base + r[-1].size : 0;
                        r_end = idx_b < type_b->cnt ?
-                               r->base : ULLONG_MAX;
+                               r->base : (phys_addr_t)ULLONG_MAX;
 
                        /*
                         * if idx_b advanced past idx_a,
                        r = &type_b->regions[idx_b];
                        r_start = idx_b ? r[-1].base + r[-1].size : 0;
                        r_end = idx_b < type_b->cnt ?
-                               r->base : ULLONG_MAX;
+                               r->base : (phys_addr_t)ULLONG_MAX;
                        /*
                         * if idx_b advanced past idx_a,
                         * break out to advance idx_a