drm/amd/display: remove duplicate call to rn_vbios_smu_get_smu_version()

Commit 78fe9f63 ("drm/amd/display: Remove DISPCLK Limit Floor for Certain SMU Versions")
added a call to rn_vbios_smu_get_smu_version() to set clk_mgr->smu_ver.
That field is initialized prior to the if-statement, already.

Fixes: 78fe9f63 (drm/amd/display: Remove DISPCLK Limit Floor for Certain SMU Versions)
Signed-off-by: Dirk Gouders <dirk@gouders.net>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sung Lee <sung.lee@amd.com>
Cc: Yongqiang Sun <yongqiang.sun@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>