clk: spear: Make structure i2s_sclk_masks constant

clk: spear: Make structure i2s_sclk_masks constant

Static structure i2s_sclk_masks, having type aux_clk_masks, is only used
when it is passed as the sixth argument to function clk_register_aux().
However, clk_register_aux() is defined with its sixth argument as const.
Hence i2s_sclk_masks is not modified by clk_register_aux, which is also
the only usage of the former. Therefore make i2s_sclk_masks constant as
it is never modified.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Link: https://lkml.kernel.org/r/20190813085714.8079-1-nishkadg.linux@gmail.com
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>