Update OpenBIOS images to SVN revision 181. Changes:

r177:
Reset fixes:
 * recalculate CRC to avoid error message and halt after reset
 * fix bug that crashed SS10/SMP when reset
r178: Remove unused variable
r179: Improved Module ID generation
r180: Add support for eccmemctl
r181: Add support for SPARCstation 20 machine type


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3804 c046a42c-6fe2-441c-8c8c-71466251a162

pc-bios/README

@@ -15,7 +15,7 @@
   firmware implementation. The goal is to implement a 100% IEEE
   1275-1994 (referred to as Open Firmware) compliant firmware.
   The included Sparc32 and Sparc64 images are built from SVN
-  revision 176.
+  revision 181.
 
 - The PXE roms come from Rom-o-Matic etherboot 5.4.2.
   pcnet32:pcnet32 -- [0x1022,0x2000]