x86: Move swiotlb initialization before dma32_free_bootmem

The commit 75f1cdf1 introduced a
bug that we initialize SWIOTLB right after dma32_free_bootmem so
we wrongly steal memory area allocated for GART with broken BIOS
earlier.

This moves swiotlb initialization before dma32_free_bootmem().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: yinghai@kernel.org
LKML-Reference: <1260759135-6450-2-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>