[BUG] sata_promise unaligned PCI accesses on sparc64

[Mikael Pettersson <mikpe@it.uu.se>]

After installing a Promise SATA300 TX2 PLUS PCI card
in a sparc64 (Ultra5) machine, the kernel complains
about three unaligned accesses during boot:

Kernel unaligned access at TPC[55c050] pdc_host_init+0x84/0xe8
Kernel unaligned access at TPC[55c074] pdc_host_init+0xa8/0xe8
Kernel unaligned access at TPC[55c094] pdc_host_init+0xc8/0xe8

Those unaligned accesses are the reads from and write to
PDC_TBG_MODE in sata_promise.c:pdc_host_init():

	/* reduce TBG clock to 133 Mhz. */
	tmp = readl(mmio + PDC_TBG_MODE);
	tmp &= ~0x30000; /* clear bit 17, 16*/
	tmp |= 0x10000;  /* set bit 17:16 = 0:1 */
	writel(tmp, mmio + PDC_TBG_MODE);

	readl(mmio + PDC_TBG_MODE);	/* flush */

Looking into this I found two strange facts:
- PDC_TBG_MODE is at offset 0x41, which clearly can never
  be 32-bit aligned.
- The 4-byte range for PDC_TBG_MODE intersects both
  PDC_INT_SEQMASK and PDC_FLASH_CTL.

Admittedly I know very little about PCI device programming,
but this doesn't look right.

/Mikael
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