clk: JZ4780: Add function for enable the second core.

Add "jz4780_core1_enable()" for enable the second core of JZ4780,
prepare for later commits.

Tested-by: H. Nikolaus Schaller <hns@goldelico.com>
Tested-by: Paul Boddie <paul@boddie.org.uk>
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Link: https://lkml.kernel.org/r/1582215889-113034-3-git-send-email-zhouyanjie@wanyeetech.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>