drm/amdkfd: Add pm_config_dequeue_wait_counts API

Update pm_update_grace_period() to more cleaner
pm_config_dequeue_wait_counts(). Previously, grace_period variable was
overloaded as a variable and a macro, making it inflexible to configure
additional dequeue wait times.

pm_config_dequeue_wait_counts() now takes in a cmd / variable. This
allows flexibility to update different dequeue wait times.

Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Reviewed-by: Jonathan Kim <jonathan.kim@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>