MIPS: Octeron: remove source file executable bit

This does not matter the least, but there is no other .[ch] file in the
repo that is executable, so clean this up.

Fixes: 29b83a64 ("MIPS: Octeon: Add PCIe link status check")
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>