PM / OPP: pass cpumask by reference

PM / OPP: pass cpumask by reference

The new use of dev_pm_opp_set_sharing_cpus resulted in a harmless compiler
warning with CONFIG_CPUMASK_OFFSTACK=y:

drivers/cpufreq/mvebu-cpufreq.c: In function 'armada_xp_pmsu_cpufreq_init':
include/linux/cpumask.h:550:25: error: passing argument 2 of 'dev_pm_opp_set_sharing_cpus' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

The problem here is that cpumask_var_t gets passed by reference, but
by declaring a 'const cpumask_var_t' argument, only the pointer is
constant, not the actual mask. This is harmless because the function
does not actually modify the mask.

This patch changes the function prototypes for all of the related functions
to pass a 'struct cpumask *' instead of 'cpumask_var_t', matching what
most other such functions do in the kernel. This lets us mark all the
other similar functions as taking a 'const' mask where possible,
and it avoids the warning without any change in object code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 947bd567f7a5 (mvebu: Use dev_pm_opp_set_sharing_cpus() to mark OPP tables as shared)
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>