drm/nouveau/disp: More DP_RECEIVER_CAP_SIZE array fixes

More arrays (and arguments) for dcpd were set to 16, when it looks like
DP_RECEIVER_CAP_SIZE (15) should be used. Fix the remaining cases, seen
with GCC 13:

../drivers/gpu/drm/nouveau/nvif/outp.c: In function 'nvif_outp_acquire_dp':
../include/linux/fortify-string.h:57:33: warning: array subscript 'unsigned char[16][0]' is partly outside array bounds of 'u8[15]' {aka 'unsigned char[15]'} [-Warray-bounds=]
   57 | #define __underlying_memcpy     __builtin_memcpy
      |                                 ^
...
../drivers/gpu/drm/nouveau/nvif/outp.c:140:9: note: in expansion of macro 'memcpy'
  140 |         memcpy(args.dp.dpcd, dpcd, sizeof(args.dp.dpcd));
      |         ^~~~~~
../drivers/gpu/drm/nouveau/nvif/outp.c:130:49: note: object 'dpcd' of size [0, 15]
  130 | nvif_outp_acquire_dp(struct nvif_outp *outp, u8 dpcd[DP_RECEIVER_CAP_SIZE],
      |                                              ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 81344372

 ("drm/nouveau/disp: move DP link config into acquire")
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <git@karolherbst.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230204184307.never.825-kees@kernel.org