Documentation/gpu: Update amdgpu documentation

7957ec8 ("drm/amdgpu: Add FRU sysfs nodes only if needed") moved
the documentation for some of the sysfs nodes to amdgpu_fru_eeprom.c.
Update the documentation accordingly.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Lijo Lazar

Documentation/gpu/amdgpu/driver-misc.rst

@@ -11,19 +11,19 @@ via sysfs
 product_name
 ------------
 
-.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
    :doc: product_name
 
 product_number
 --------------
 
-.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
-   :doc: product_name
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: product_number
 
 serial_number
 -------------
 
-.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
    :doc: serial_number
 
 unique_id