ghostscript: fix run failure on mpc8315e

ghostscript: fix run failure on mpc8315e

When run gs on mpc8315, it fails with:
GPL Ghostscript 9.02: ./psi/interp.c(291): Fatal error -20 in gs_interp_init!
It is caused by cross compile.

Accoding to the ghostscript document on:
http://pages.cs.wisc.edu/~ghost/doc/cvs/Make.htm#Cross-compiling
it needs some manual work, so import patches from WindRiver Linux.

Update to using oe way to add arch.h, thanks to Richard.

Signed-off-by: Kang Kai <kai.kang@windriver.com>