fix: do not use rbx register in asm!()

error: invalid register `rbx`: rbx is used internally by LLVM and
cannot be used as an operand for inline asm

See:
rust-lang/rust#84658 (comment)

and:
https://github.com/rust-lang/rust/pull/84658/files#diff-d7283132d97a993fad4e2d491ac883dbce4e17fe248cdf37fa3f9334e2a5a115

Author: haraldh

src/attestation_types/ti.rs

@@ -50,10 +50,12 @@ impl TargetInfo {
         let mut report = core::mem::MaybeUninit::<report::Report>::uninit();
 
         asm!(
+            "xchg {RBX}, rbx",
             "enclu",
+            "mov rbx, {RBX}",
 
+            RBX = inout(reg) self => _,
             in("rax") EREPORT,
-            in("rbx") self,
             in("rcx") data.0.as_ptr(),
             in("rdx") report.as_mut_ptr(),
         );