mmc: sdhci-of-arasan: Change code style of mapping the syscon field

Change code style of mapping the syscon in sdhci_arasan_update_support64b()
for readability and consistency.

Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20210111155001.12307-3-muhammad.husaini.zulkifli@intel.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>