board: ti: Move fastboot functions out of TI_SECURE_DEVICE ifdef

When these were moved from mach-omap2 to board files they got placed
inside TI_SECURE_DEVICE ifdef block, they are not secure only, move
them up and out.

Fixes: 413b9077 ("ti: fastboot: Move weak overrides to board files")
Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>