x86/HVM: use XVFREE() in hvmemul_cache_destroy()

My adjustments to move from xmalloc() et al to respective xvmalloc()
flavors was flawed - a freeing instance wasn't converted.

Fixes: 23d60dbb04 ("x86/HVM: allocate emulation cache entries dynamically")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-Acked-by: Oleksii Kurochko<oleksii.kurochko@gmail.com>

xen/arch/x86/include/asm/hvm/emulate.h

@@ -123,7 +123,7 @@ static inline void hvmemul_cache_destroy(struct vcpu *v)
     unsigned int i;
 
     for ( i = 0; i < ARRAY_SIZE(v->arch.hvm.hvm_io.mmio_cache); ++i )
-        XFREE(v->arch.hvm.hvm_io.mmio_cache[i]);
+        XVFREE(v->arch.hvm.hvm_io.mmio_cache[i]);
     XVFREE(v->arch.hvm.hvm_io.cache);
 }
 bool hvmemul_read_cache(const struct vcpu *v, paddr_t gpa,