drm/amd: Do not include <linux/export.h> when unused

Fix the following compile time warning when building with W=1:

warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c

@@ -24,7 +24,6 @@
  *          Alex Deucher
  */
 
-#include <linux/export.h>
 #include <linux/pci.h>
 
 #include <drm/drm_edid.h>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -22,7 +22,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/export.h>
 #include <linux/err.h>
 #include <linux/fs.h>
 #include <linux/file.h>

drivers/gpu/drm/amd/amdkfd/kfd_flat_memory.c

@@ -23,7 +23,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/export.h>
 #include <linux/err.h>
 #include <linux/fs.h>
 #include <linux/sched.h>