clover: add stubs for SVM

clover: add stubs for SVM

although most of those are 2.0 core functions, there is
cl_arm_shared_virtual_memory to expose those in a 1.2 context. But we
should be able to expose this extension with 1.1 as well as there is no
technicaly reason why this shouldn't work.

v2: move svm functions into existing files
v3: rename func args to match convention

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Pierre Moreau <dev@pmoreau.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/2076>