ACPICA: Fix for acpi_reallocate_root_table for incorrect root table copy

When copying the root table to the new allocation, the length
used was incorrect. The new size was used instead of the current
table size, meaning too much data was copied.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>