configure: Do not build pc-bios/optionrom on Haiku

configure: Do not build pc-bios/optionrom on Haiku

Compilation of pc-bios/optionrom fails on Haiku with:

   BUILD   pvh.img
 ld: pvh_main.o: in function `pvh_load_kernel':
 pc-bios/optionrom/pvh_main.c:73: undefined reference to `GLOBAL_OFFSET_TABLE_'
 Makefile:57: recipe for target 'pvh.img' failed
 make[1]: *** [pvh.img] Error 1

Let's simply disable it, like it is already done on macOS and Solaris.

Message-Id: <20201114165137.15379-3-thuth@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>