Scope gva_code_xref by an explicit prot_any argument

It hard-coded VR_X, so a target whose page tables expose no executable
region silently yielded zero xrefs. Callers now pass the scope (VR_X to
restrict to code, VR_R when the X bit is unavailable); the decoder and
exact target match remain the correctness gate. Mirrors the prot_any
parameter gva_imm_xref already carries.

src/handlers/codescan.c

@@ -115,10 +115,10 @@ static int xref_sweep_cb(void* u, const uint8_t* data, size_t len,
 }
 
 int gva_code_xref(vmie_mem* m, uintptr_t cr3, uint64_t lo, uint64_t hi,
-                  uint64_t target_va, uint64_t* out, int max) {
+                  uint32_t prot_any, uint64_t target_va, uint64_t* out, int max) {
     struct xref_cb c; memset(&c, 0, sizeof c);
     c.target = target_va; c.out = out; c.max = max;
-    if (gva_sweep(m, cr3, lo, hi, VR_X, X86_MAX_INSN, xref_sweep_cb, &c) < 0) {
+    if (gva_sweep(m, cr3, lo, hi, prot_any, X86_MAX_INSN, xref_sweep_cb, &c) < 0) {
         return -1;
     }
     return c.n;