KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()

KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()

Keep sparse quiet by explicitly casting endianness conversion
when swapping S1 and S2 descriptors.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202511260246.JQDGsQKa-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202511260344.9XehvH5Q-lkp@intel.com/
Fixes: c59ca4b5b0c3f ("KVM: arm64: Implement HW access flag management in stage-1 SW PTW")
Fixes: 39db933ba67f8 ("KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://msgid.link/20251125204848.1136383-1-maz@kernel.org
Signed-off-by: Oliver Upton <oupton@kernel.org>