KVM: arm64: nvhe: Eliminate kernel-doc warnings

Don't use begin-kernel-doc notation (/**) for comments that are not in
kernel-doc format.

This prevents these kernel-doc warnings:

arch/arm64/kvm/hyp/nvhe/switch.c:126: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Disable host events, enable guest events
arch/arm64/kvm/hyp/nvhe/switch.c:146: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Disable guest events, enable host events
arch/arm64/kvm/hyp/nvhe/switch.c:164: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Handler for protected VM restricted exceptions.
arch/arm64/kvm/hyp/nvhe/switch.c:176: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Handler for protected VM MSR, MRS or System instruction execution in AArch64.
arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: Function parameter or member 'vcpu' not described in 'kvm_handle_pvm_fpsimd'
arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: Function parameter or member 'exit_code' not described in 'kvm_handle_pvm_fpsimd'
arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: expecting prototype for Handler for protected floating(). Prototype was for kvm_handle_pvm_fpsimd() instead

Fixes: 09cf57eb ("KVM: arm64: Split hyp/switch.c to VHE/nVHE")
Fixes: 1423afcb ("KVM: arm64: Trap access to pVM restricted features")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: David Brazdil <dbrazdil@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220430050123.2844-1-rdunlap@infradead.org