This fixes the warning below by changing the prototype to a location
that's actually included by the .c files that call
amdgpu_kms_compat_ioctl:
 warning: no previous prototype for ‘amdgpu_kms_compat_ioctl’
 [-Wmissing-prototypes]
 37 | long amdgpu_kms_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
    |      ^~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
 u32 amdgpu_get_vblank_counter_kms(struct drm_crtc *crtc);
 int amdgpu_enable_vblank_kms(struct drm_crtc *crtc);
 void amdgpu_disable_vblank_kms(struct drm_crtc *crtc);
-long amdgpu_kms_compat_ioctl(struct file *filp, unsigned int cmd,
-                            unsigned long arg);
 int amdgpu_info_ioctl(struct drm_device *dev, void *data,
                      struct drm_file *filp);
 
 
 long amdgpu_drm_ioctl(struct file *filp,
                      unsigned int cmd, unsigned long arg);
 
+long amdgpu_kms_compat_ioctl(struct file *filp,
+                            unsigned int cmd, unsigned long arg);
+
 #endif