drm/radeon/kms: fix bad cast/shift in evergreen.c
drm/radeon/kms: fix bad cast/shift in evergreen.c

Missing parens.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=30718

Reported-by: Dave Gilbert <974f068c1a0f77888ff3f4e29cc3ce5ddb2d9058@treblig.org>
Signed-off-by: Alex Deucher <bf84f557a1e54fd62cd73c6847f7d9df60e9fbef@gmail.com>
Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

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