arm: ti: environment: Move <environment/ti/boot.h> in to <configs/ti_omap5_common.h>

This include file is only used by ti_omap5_common.h.  Further, the move
is towards using the generic distro boot framework and not this set of
macros.  Start by moving all of the contents in directly to where they
are used.

Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210701132612.7559-2-trini@konsulko.com