Remove the empty 'pxa2xx_pic_initfn' and it's
setup code in the 'pxa2xx_pic_class_init'

Signed-off-by: xiaoqiang zhao <zxq_yx_007@163.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>