uboot-phytec

common/spl/Kconfig: Use 'if SPL' / 'if TPL' guards

Much of the entries here simply depend on SPL (or TPL).  Instead of this
redundancy use if SPL / if TPL to guard the rest of the choices and only
show them when we have the relevant option enabled.

Signed-off-by: Tom Rini <trini@konsulko.com>