drm/amdkfd: avoid conflicting address mappings

[Why]
Avoid conflict with address ranges mapped by SVM
mechanism that try to be allocated again through
ioctl_alloc in the same process. And viceversa.

[How]
For ioctl_alloc_memory_of_gpu allocations
Check if the address range passed into ioctl memory
alloc does not exist already in the kfd_process
svms->objects interval tree.

For SVM allocations
Look for the address range into the interval tree VA from
the VM inside of each pdds used in a kfd_process.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>