a) Because I would like to flush out bugs.
b) Because I want a default that works for everyone.
c) Because with MSI we have a potential for large irq counts on most systems.
d) Because anyone who disagrees with me can send a patch and fix
the default.
e) Because with the default number of cpus we can very close to needing
this many irqs in the worst case.
f) This is much better than previous to my patch and setting NR_CPUS=255
and getting 8K IRQS.
g) Because I probably should have been more inventive than copying the
NR_IRQS text, but when I did the wording sounded ok to me.