sh: clkfwk: fixup clk_rate_table_build parameter in div6 clock

div6 clock should not use arch_flags for clk_rate_table_build,
because SH_CLK_DIV6_EXT doesn't care .arch_flags.
clk->freq_table[] will be all CPUFREQ_ENTRY_INVALID without this patch.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: stable@kernel.org
Signed-off-by: Paul Mundt <lethal@linux-sh.org>