acpi: Fix an infinite loop in acpi_table_add

Commit d729bb9a77 has a typo, causing an
infinite loop in acpi_table_add.

Signed-off-by: Vincent Minet <vincent@vincent-minet.net>
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

hw/acpi.c

@@ -161,7 +161,7 @@ int acpi_table_add(const char *t)
 
         /* off < length is necessary because file size can be changed
            under our foot */
-        while(s.st_size && off < length); {
+        while(s.st_size && off < length) {
             int r;
             r = read(fd, p + off, s.st_size);
             if (r > 0) {