Update to SeaBIOS 0.5.1

  5da6833 Update version to 0.5.1
  669c991 Fix sign error preventing incorrect memory over 4gig calculation.
  7e6bd3e Minor - better indent assembler in int1587.
  48cf232 Add comment explaining why mptable is in low memory.
  643062f Add int1589 support.
  085debd Set FDPT in irq table even for small drives.
  7c1b186 Reduce #ifs by weeding out some cross-chunk function definitions.
  f9b25d3 Fix vgahook sign issue; add warning to build to catch future cases.
  3862b2d vgabios: Fix compile error due to fixed prototypes.
  1ca05b0 Be sure to add "void" to all function prototypes that take no args.
  b5bb9db mptable: Reset pinmask on new bus or device.
  8918989 Detect latest FC12 gcc -combine breakage.
  c9d3c2d Minor vga binary cleanups.
  9a8609f Make MTRR region 0xc0000-0x100000 be cached.
  fdca418 Force a link error if a function is used from the wrong code chunk.
  dad41d9 Add __noreturn define for __attribute__((noreturn)).
  c003148 Implement native 32bit APM support.
  5c99b6c Commit compiled dsdt file; misc comment updates.
  29f4b91 prevent acpi from rerouting SCI interrupt
  4c94b7e enumerate all PCI buses in mptable
  871e0a0 Add support for 32bit PCI BIOS entry.
  eda2c83 Only add "addr32" to memory accesses that require them.
  52a300f Introduce MODESEGMENT define; rename VISIBLE32 to VISIBLE32FLAT.
  fe2c3ee Allocate smbios in temp space and copy into final location.
  b164d2c Clear user reserved interrupts (0x60-0x66).
  d9104ff Remove pci_bios_bigmem_addr; set pci_bios_mem_addr=0xe0000000
  14021f2 Add initial support for ATA DMA.
  8362699 Allocate mptable in temp space and copy into final location.
  979862e Also report memory over 4G during init.
  928d4df provide correct pci routing information in mptable
  afc02da Add symbolic definitions for MTRR code.
  fb214dc Fix yield() so it works from boot code.
  2ceeec9 Fix potential build failure due to text16 section being too large.
  a2195e4 Increase version in preparation for next release.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
