bochs/bios: Fix build

Currently, this project does not build on Ubuntu. "make" fails in the
bochs/bios/ directory with the following error:

 ld -o rombios32.out -T ./rombios32.ld rombios32start.o rombios32.o
 ld: section .eh_frame loaded at [00000000000e3e40,00000000000e453f]
  overlaps section .data loaded at [00000000000e3e40,00000000000e3e43]
 make[1]: *** [rombios32.out] Error 1

Build environment:

 - Ubuntu 14.04 x86_64
 - gcc (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
 - GNU ld (GNU Binutils for Ubuntu) 2.24

Back-porting the following patch from the upstream Bochs codebase fixes
this issue:

------------------------------------------------------------------------
r11179 | vruppert | 2012-05-13 06:25:09 +0800 (Sun, 13 May 2012) [1]

- discard "eh_frame" (compilation fix from Debian patches)

------------------------------------------------------------------------

[1] http://sourceforge.net/p/bochs/code/11179

Change-Id: Icc0d8ee4738c71e8dc02fe9e328923a4d968deac
Signed-off-by: Yu Ning <yu.ning@intel.com>
diff --git a/bochs/bios/rombios32.ld b/bochs/bios/rombios32.ld
index ff765c8..fe0414a 100644
--- a/bochs/bios/rombios32.ld
+++ b/bochs/bios/rombios32.ld
@@ -12,6 +12,7 @@
         /DISCARD/ : { *(.stab)
                      *(.stabstr)
                      *(.comment)
+                     *(.eh_frame)
                      *(.note)
                   }
 }