[mips64el] Make mips64el use int-ll64.h

This will fix compilation error:
../../third_party/libdrm/src/tests/modetest/modetest.c:388:11: error:
format specifies type 'unsigned long long' but the argument has type '__u64' (aka 'unsigned long') [-Werror,-Wformat]
                               prop->enums[i].value);
                               ^~~~~~~~~~~~~~~~~~~~

Change-Id: Id9881f6ae1831812e851f0d1e62998c383355430
Reviewed-on: https://chromium-review.googlesource.com/1194068Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587762}

build/config/compiler/BUILD.gn

@@ -928,6 +928,7 @@ config("compiler_cpu_abi") {
 
       cflags += [ "-m${mips_float_abi}-float" ]
     } else if (current_cpu == "mips64el") {
+      cflags += [ "-D__SANE_USERSPACE_TYPES__" ]
       ldflags += [ "-Wl,--hash-style=sysv" ]
       if (custom_toolchain == "") {
         if (is_clang) {