powerpc/ibmebus: more meaningful variable name

Choose a more meaningful name for better System.map readability and
autopsy value etc.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --cc arch/powerpc/kernel/ibmebus.c
Simple merge