[AMDGPU] Tweak predicates for image_bvh_intersect_ray instructions

Don't override SubtargetPredicate since that is already set in the
base classes for the appropriate subtarget like MIMG_gfx10. Use
OtherPredicates instead for consistency with the way we handle
features like HasImageInsts and HasExtendedImageInsts. NFC.

Differential Revision: https://reviews.llvm.org/D120909