drm/amd/pm: Fix a memory leak in an error handling path in 'vangogh_tables_init()'

'watermarks_table' must be freed instead 'clocks_table', because
'clocks_table' is known to be NULL at this point and 'watermarks_table' is
never freed if the last kzalloc fails.

Fixes: c98ee897

 ("drm/amd/pm: add the fine grain tuning function for vangogh")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>