drm/msm: adreno: fix build error without debugfs

drm/msm: adreno: fix build error without debugfs

BugLink: http://bugs.launchpad.net/bugs/1682130
commit 280489daa68bd20364b322c11e3f429a0212c611 upstream.

The newly added a5xx support fails to build when debugfs is diabled:

drivers/gpu/drm/msm/adreno/a5xx_gpu.c:849:4: error: 'struct msm_gpu_funcs' has no member named 'show'
drivers/gpu/drm/msm/adreno/a5xx_gpu.c:849:11: error: 'a5xx_show' undeclared here (not in a function); did you mean 'a5xx_irq'?

This adds a missing #ifdef.

Fixes: b5f103ab98c7 ("drm/msm: gpu: Add A5XX target support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>