KVM: arm64: Initialize struct kvm_s2_fault completely at declaration

KVM: arm64: Initialize struct kvm_s2_fault completely at declaration

Simplify the initialization of struct kvm_s2_fault in user_mem_abort().

Instead of partially initializing the struct via designated initializers
and then sequentially assigning the remaining fields (like write_fault
and topup_memcache) further down the function, evaluate those
dependencies upfront.

This allows the entire struct to be fully initialized at declaration. It
also eliminates the need for the intermediate fault_data variable and
its associated fault pointer, reducing boilerplate.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>