drm/amdgpu: Fix error handling in amdgpu_ras_add_bad_pages

It ensures that appropriate error codes are returned when an error
condition is detected

Fixes the below;
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:2849 amdgpu_ras_add_bad_pages() warn: missing error code here? 'amdgpu_umc_pages_in_a_row()' failed.
drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:2884 amdgpu_ras_add_bad_pages() warn: missing error code here? 'amdgpu_ras_mca2pa()' failed.

v2: s/-EIO/-EINVAL, retained the use of -EINVAL from
    amdgpu_umc_pages_in_a_row & and amdgpu_ras_mca2pa_by_idx, when the
    RAS context is not initialized or the convert_ras_err_addr function is
    unavailable. (Thomas)

V3: Returning 0 as the absence of eh_data is acceptable. (Tao)

Fixes: a8d133e6 ("drm/amdgpu: parse legacy RAS bad page mixed with new data in various NPS modes")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: YiPeng Chai <yipeng.chai@amd.com>
Cc: Tao Zhou <tao.zhou1@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>