drm/amd/display: Fix build breakage with CONFIG_DEBUG_FS=n

drm/amd/display: Fix build breakage with CONFIG_DEBUG_FS=n

After commit 8799c0be89eb ("drm/amd/display: Fix vblank refcount in vrr
transition"), a build with CONFIG_DEBUG_FS=n is broken due to a
misplaced brace, along the lines of:

  In file included from drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_trace.h:39,
                   from drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:41:
  drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c: At top level:
  ./include/drm/drm_atomic.h:864:9: error: expected identifier or ‘(’ before ‘for’
    864 |         for ((__i) = 0;                                                 \
        |         ^~~
  drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:8317:9: note: in expansion of macro ‘for_each_new_crtc_in_state’
   8317 |         for_each_new_crtc_in_state(state, crtc, new_crtc_state, j)
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~

Move the brace within the #ifdef so that the file can be built with or
without CONFIG_DEBUG_FS.

Fixes: 8799c0be89eb ("drm/amd/display: Fix vblank refcount in vrr transition")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>