drm/radeon/kms: fix bandwidth calculation when sideport is present
drm/radeon/kms: fix bandwidth calculation when sideport is present

Fixes fdo bug 27529:
https://bugs.freedesktop.org/show_bug.cgi?id=27529

Reported-by: a369c1df989c52ae8376c89c9157be30936062bf@yahoo.fr
Signed-off-by: Alex Deucher <bf84f557a1e54fd62cd73c6847f7d9df60e9fbef@gmail.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas