The RTCCTRL reg of LS1C is obselete.
Writing this reg will cause system hang.

Fixes: 60219c56 ("MIPS: Add RTC support for Loongson1C board")
Signed-off-by: NYang Ling <gnaygnil@gmail.com>
Tested-by: NKeguang Zhang <keguang.zhang@gmail.com>
Acked-by: NKeguang Zhang <keguang.zhang@gmail.com>
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>