spi: sprd: switch the sequence of setting WDG_LOAD_LOW and _HIGH

spi: sprd: switch the sequence of setting WDG_LOAD_LOW and _HIGH

The watchdog counter consists of WDG_LOAD_LOW and WDG_LOAD_HIGH,
which would be loaded to watchdog counter once writing WDG_LOAD_LOW.

Fixes: 97a029b5d4c1 ("spi: sprd: Add the support of restarting the system")
Signed-off-by: Lingling Xu <ling_ling.xu@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20200602082415.5848-1-zhang.lyra@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>