ANDROID: KVM: arm64: Introduce KVM_CAP_ARM_PROTECTED_VM to set/query PVM firmware

Expose a new capability, KVM_CAP_ARM_PROTECTED_VM, for protected VMs
which allows the size of the PVM firmware region to be discovered from
userspace and for the firmware load address to be specified if it is
required.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 254819795
Change-Id: I819b9b2cfa227f1a0607a8f683aa01d4ae50704f
Signed-off-by: Quentin Perret <qperret@google.com>