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>
diff --git a/configs/P2020RDB-PC_defconfig b/configs/P2020RDB-PC_defconfig
index 48451fd..8029c63 100644
--- a/configs/P2020RDB-PC_defconfig
+++ b/configs/P2020RDB-PC_defconfig
@@ -22,6 +22,7 @@
 CONFIG_BOARD_EARLY_INIT_R=y
 # CONFIG_MISC_INIT_R is not set
 CONFIG_SPL_MAX_SIZE=0x20000
+CONFIG_SPL_SYS_CCSR_DO_NOT_RELOCATE=y
 CONFIG_SPL_FLUSH_IMAGE=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_AUTO_COMPLETE is not set