drm/nouveau: exec: fix ioctl kernel-doc warning

kernel-doc emits a warning:

include/uapi/drm/nouveau_drm.h:49: warning: Cannot understand  * @NOUVEAU_GETPARAM_EXEC_PUSH_MAX
 on line 49 - I thought it was a doc line

We don't have a way to document a macro value via kernel-doc, so
change the "/**" kernel-doc marker to a C comment and format the comment
more like a kernel-doc comment for consistency.

Fixes: d59e75e ("drm/nouveau: exec: report max pushs through getparam")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: Karol Herbst <[email protected]>
Cc: Lyude Paul <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Bragatheswaran Manickavel <[email protected]>
Reviewed-by: Lyude Paul <[email protected]>
Signed-off-by: Danilo Krummrich <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: rddunlap

include/uapi/drm/nouveau_drm.h

@@ -45,8 +45,8 @@ extern "C" {
 #define NOUVEAU_GETPARAM_HAS_BO_USAGE    15
 #define NOUVEAU_GETPARAM_HAS_PAGEFLIP    16
 
-/**
- * @NOUVEAU_GETPARAM_EXEC_PUSH_MAX
+/*
+ * NOUVEAU_GETPARAM_EXEC_PUSH_MAX - query max pushes through getparam
  *
  * Query the maximum amount of IBs that can be pushed through a single
  * &drm_nouveau_exec structure and hence a single &DRM_IOCTL_NOUVEAU_EXEC