ddr: altera: Compile ALTERA SDRAM in SPL only

Compile ALTERA_SDRAM driver in SPL only.
Rename ALTERA_SDRAM to SPL_ALTERA_SDRAM.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
index 8f7b79f..ea316d0 100644
--- a/arch/arm/mach-socfpga/Kconfig
+++ b/arch/arm/mach-socfpga/Kconfig
@@ -26,7 +26,7 @@
 
 config TARGET_SOCFPGA_ARRIA10
 	bool
-	select ALTERA_SDRAM
+	select SPL_ALTERA_SDRAM
 	select SPL_BOARD_INIT if SPL
 	select CLK
 	select SPL_CLK if SPL
@@ -47,7 +47,7 @@
 
 config TARGET_SOCFPGA_GEN5
 	bool
-	select ALTERA_SDRAM
+	select SPL_ALTERA_SDRAM
 	imply FPGA_SOCFPGA
 	imply SPL_STACK_R
 	imply SPL_SYS_MALLOC_SIMPLE