drm/amdgpu: fix i2s_pdata out of bound array access

Fixed following Smatch static checker warning:

    drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c:393 acp_hw_init()
    error: buffer overflow 'i2s_pdata' 3 <= 3
    drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c:396 acp_hw_init()
    error: buffer overflow 'i2s_pdata' 3 <= 3

Fixes: 4c33e517 ("drm/amdgpu: create I2S platform devices for Jadeite platform")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>