There's a small issue with drivers/usb/serial/keyspan_usa90msg.h

The definition for MSR_RI conflicts with some PowerPC CPU definition
(MSR is the Machine State Register on PPC and processor.h defines
MSR_RI globally). This definition doesn't seem to be used in any .c
in drivers/usr/serial though, so I beleive it could be easily renamed
to something a bit less prone to conflict ;) Changing the PPC definition
would be a lot nastier.