KVM: SVM: Fix uninitialized variable bug

If snp_lookup_rmpentry() fails then "assigned" is printed in the error
message but it was never initialized.  Initialize it to false.

Fixes: dee5a47c ("KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Message-ID: <20240612115040.2423290-3-dan.carpenter@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/sev.c

@@ -2276,7 +2276,7 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn_start, kvm_pfn_t pf
 
 	for (gfn = gfn_start, i = 0; gfn < gfn_start + npages; gfn++, i++) {
 		struct sev_data_snp_launch_update fw_args = {0};
-		bool assigned;
+		bool assigned = false;
 		int level;
 
 		ret = snp_lookup_rmpentry((u64)pfn + i, &assigned, &level);