nxp: Finish migration of SYS_FSL_SRDS_[12] to Kconfig

As this is used on both ARM and PowerPC platforms, this needs to be
listed in arch/Kconfig.nxp and match how they're currently used by
select'ing them under the required PowerPC ARCH_xxx options.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/Kconfig.nxp b/arch/Kconfig.nxp
index 645b4ce..6e1c44b 100644
--- a/arch/Kconfig.nxp
+++ b/arch/Kconfig.nxp
@@ -286,4 +286,13 @@
 config SYS_DPAA_FMAN
 	bool
 
+config SYS_FSL_SRDS_1
+	bool
+
+config SYS_FSL_SRDS_2
+	bool
+
+config SYS_HAS_SERDES
+	bool
+
 endmenu