siemens: cosmetic: remove unused and rename defines

For dxr2 board DXR2_IOCTRL_VAL is set by data in EEPROM. In pxm2
board it does not make sense to have dxr2 as prefix. Replace it with
more meaningful DDR prefix.

Signed-off-by: Samuel Egli <samuel.egli@siemens.com>
Cc: Pascal Bach <pascal.bach@siemens.com>
Cc: Roger Meier <r.meier@siemens.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
diff --git a/board/siemens/pxm2/board.c b/board/siemens/pxm2/board.c
index 98083d5..64e69dc 100644
--- a/board/siemens/pxm2/board.c
+++ b/board/siemens/pxm2/board.c
@@ -70,11 +70,11 @@
 };
 
 const struct ctrl_ioregs ioregs = {
-	.cm0ioctl		= DXR2_IOCTRL_VAL,
-	.cm1ioctl		= DXR2_IOCTRL_VAL,
-	.cm2ioctl		= DXR2_IOCTRL_VAL,
-	.dt0ioctl		= DXR2_IOCTRL_VAL,
-	.dt1ioctl		= DXR2_IOCTRL_VAL,
+	.cm0ioctl		= DDR_IOCTRL_VAL,
+	.cm1ioctl		= DDR_IOCTRL_VAL,
+	.cm2ioctl		= DDR_IOCTRL_VAL,
+	.dt0ioctl		= DDR_IOCTRL_VAL,
+	.dt1ioctl		= DDR_IOCTRL_VAL,
 };
 
 	config_ddr(DDR_PLL_FREQ, &ioregs, &pxm2_ddr3_data,
diff --git a/include/configs/dxr2.h b/include/configs/dxr2.h
index 75f7812..4612f85 100644
--- a/include/configs/dxr2.h
+++ b/include/configs/dxr2.h
@@ -20,7 +20,6 @@
 #include "siemens-am33x-common.h"
 
 #define CONFIG_SYS_MPUCLK	275
-#define DXR2_IOCTRL_VAL	0x18b
 #define DDR_PLL_FREQ	303
 #undef CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC
 
diff --git a/include/configs/pxm2.h b/include/configs/pxm2.h
index 6276d43..d75d562 100644
--- a/include/configs/pxm2.h
+++ b/include/configs/pxm2.h
@@ -21,7 +21,7 @@
 #include "siemens-am33x-common.h"
 
 #define CONFIG_SYS_MPUCLK	720
-#define DXR2_IOCTRL_VAL		0x18b
+#define DDR_IOCTRL_VAL		0x18b
 #define DDR_PLL_FREQ		266
 
 #define BOARD_DFU_BUTTON_GPIO	59