Add -pkvm_experimental to the kernel prebuilt

Current name suggests that android14-6.1 GKI can be run as guest, which
is not true. Resolve this confusion by explicitly specifying
-pkvm_experimental to the name, which points out that this image was
built from the android14-6.1-pkvm_experimental branch.

Bug: 329383978
Test: AVF presubmit
Change-Id: I6efc1fce3bd8dc9bd5ea171502aab7d8c7da9b9d
1 file changed