clk: socfpga: Fix section mismatch warning

WARNING: drivers/clk/socfpga/built-in.o(.data+0xc0): Section mismatch in
reference from the variable socfpga_child_clocks to the function
.init.text:socfpga_pll_init()
The variable socfpga_child_clocks references
the function __init socfpga_pll_init()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: drivers/clk/socfpga/built-in.o(.data+0x184): Section mismatch in
reference from the variable socfpga_child_clocks to the function
.init.text:socfpga_periph_init()
The variable socfpga_child_clocks references
the function __init socfpga_periph_init()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: drivers/clk/socfpga/built-in.o(.data+0x248): Section mismatch in
reference from the variable socfpga_child_clocks to the function
.init.text:socfpga_gate_init()
The variable socfpga_child_clocks references
the function __init socfpga_gate_init()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Reported-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>