arm: omap3: Cleanup sys_info to fit OMAP3 booting with LTO

With LTO enabled, some functions appear to be optimized in a
way that causes hanging on some OMAP3 boards after some
unrelated patches were applied.  The solution appears to make
several functions __used.  There also appears be to be some
dead code, so remove it while cleaning this up.

This has been tested on a general purpose OMAP3530, DM3730,
and AM3517.

Signed-off-by: Adam Ford <aford173@gmail.com>