clk: thead: th1520-ap: fix parent of padctrl0 clock

clk: thead: th1520-ap: fix parent of padctrl0 clock

The padctrl0 clock seems to be a child of the perisys_apb4_hclk clock,
gating the later makes padctrl0 registers stuck too.

Fix this relationship.

Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Drew Fustini <fustini@kernel.org>
Reviewed-by: Troy Mitchell <troy.mitchell@linux.dev>
Signed-off-by: Drew Fustini <fustini@kernel.org>