hw/acpi: remove unnecessary variable acpi_table_builtin

acpi_table_builtin is now always false, it is not necessary to check it
again.

This patch just removes it.
Signed-off-by: NWei Yang <richardw.yang@linux.intel.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NIgor Mammedov <imammedo@redhat.com>
Message-Id: <20190214084939.20640-4-richardw.yang@linux.intel.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

hw/acpi/core.c

@@ -307,8 +307,6 @@ out:
     error_propagate(errp, err);
 }
 
-static bool acpi_table_builtin = false;
-
 unsigned acpi_table_len(void *current)
 {
     struct acpi_table_header *hdr = current - sizeof(hdr->_length);
@@ -324,7 +322,7 @@ void *acpi_table_hdr(void *h)
 
 uint8_t *acpi_table_first(void)
 {
-    if (acpi_table_builtin || !acpi_tables) {
+    if (!acpi_tables) {
         return NULL;
     }
     return acpi_table_hdr(acpi_tables + ACPI_TABLE_PFX_SIZE);