cpufreq/amd-pstate: Fix the scaling_max_freq setting on shared memory CPPC systems

cpufreq/amd-pstate: Fix the scaling_max_freq setting on shared memory CPPC systems

On shared memory CPPC systems, with amd_pstate=active mode, the change
in scaling_max_freq doesn't get written to the shared memory
region. Due to this, the writes to the scaling_max_freq sysfs file
don't take effect. Fix this by propagating the scaling_max_freq
changes to the shared memory region.

Fixes: ffa5096a7c33 ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors")
Reported-by: David Arcari <darcari@redhat.com>
Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20240702081413.5688-3-Dhananjay.Ugwekar@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>