kvm: Fix potential resource leak (missing fclose)

This leak was detected by cppcheck.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/i386/kvm/pci-assign.c

@@ -548,6 +548,7 @@ static int get_real_id(const char *devpath, const char *idname, uint16_t *val)
     if (fscanf(f, "%li\n", &id) == 1) {
         *val = id;
     } else {
+        fclose(f);
         return -1;
     }
     fclose(f);