i386/tdx: Remove the redundant qemu_mutex_init(&tdx->lock)

i386/tdx: Remove the redundant qemu_mutex_init(&tdx->lock)

Commit 40da501d8989 ("i386/tdx: handle TDG.VP.VMCALL<GetQuote>") added
redundant qemu_mutex_init(&tdx->lock) in tdx_guest_init by mistake.

Fix it by removing the redundant one.

Fixes: 40da501d8989 ("i386/tdx: handle TDG.VP.VMCALL<GetQuote>")
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Link: https://lore.kernel.org/r/20250717103707.688929-1-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>