ppc / layerscape: Clean up CONFIG_SYS_CCSR_DO_NOT_RELOCATE usage

ppc / layerscape: Clean up CONFIG_SYS_CCSR_DO_NOT_RELOCATE usage

A number of PowerPC platforms define this, for SPL.  To move this to
Kconfig, it needs to be CONFIG_SPL_SYS_CCSR_DO_NOT_RELOCATE, so use
CONFIG_IS_ENABLED() to check for usage.  A number of layerscape
platforms bring this logic from PowerPC, but only need a small part of
it, for the fman driver.  Remove their unused portion at least.

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