Revert "rockchip: Move the MMC setup check earlier"

Boot Rom wouldn't initialize sdmmc while booting from eMMC. We need to
setup sdmmc gpio, otherwise we will hit an error below:

=>mmc info
blk_get_device: if_type=6, devnum=0: dwmmc@ff0c0000.blk, 6, 0
uclass_find_device_by_seq: 0 -1
uclass_find_device_by_seq: 0 0
   - -1 -1
   - -1 0
   - found
uclass_find_device_by_seq: 0 1
   - -1 -1
   - -1 0
   - not found
fdtdec_get_int_array: interrupts
get_prop_check_min_len: interrupts
Buswidth = 1, clock: 0
Buswidth = 1, clock: 400000
Sending CMD0
dwmci_send_cmd: Timeout on data busy
dwmci_send_cmd: Timeout on data busy
dwmci_send_cmd: Timeout on data busy
dwmci_send_cmd: Timeout on data busy

This reverts commit 6efeeea7.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>