Update OpenBIOS images to SVN r237.

Update OpenBIOS images to SVN r237.

Changes:
r219: Fix #size-cells for HelenOS, add /openprom/version node
r220: Fix typo
r221: More realistic mmu_translate
r222: Fix device names to allow Net/OpenBSD to boot
r223: add set-callback for Aurora 2.0
r224: Switch keyboard controller to translated mode so it works as expected
r225: Add mmu release (claim added in r219)
r226: Set variable defaults before nvram_init also for Sparc64 (cf. r136)
r227: Use nvram boot-args and boot-device variables also for Sparc64 (cf. r137)
r228: Fix compilation on OpenBSD: avoid accidental system include file use
r229: Rename /packages/client-iface to /openprom/client-services
r230

From Igor V. Kovalenko:

This openbios-grubfs-ext2fs-block.patch fixes a problem where inode
pointer is truncated to 32bit integer and then sign-extended to 64bit
integer while passing second pointer argument to ext2_rdfsb.

r231: Fix pad alignment
r232: Remove package finding code that finds unrelated packages
r233: Fix virtual to physical address translation (Igor Kovalenko)
r234: Implement itlb/dtlb directed writes (Igor Kovalenko)
r235: Fix warnings that would be caused by ld flag --warn-common
r236: Enable ld flag --warn-common
r237: Use the firmware device introduced in Qemu SVN r5256

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5262 c046a42c-6fe2-441c-8c8c-71466251a162