ppc4xx: Fix misspelled CONFIG_440SPE/440EPX/GRX config options

We use upper case letters for the AMCC processor defines (like
CONFIG_440SPE) in U-Boot. So the 440SPe is labeled CONFIG_440SPE and
not CONFIG_440SPe. This patch fixes the last misspelled config options.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/cpu/ppc4xx/4xx_uart.c b/cpu/ppc4xx/4xx_uart.c
index ffbc222..a7587d4 100644
--- a/cpu/ppc4xx/4xx_uart.c
+++ b/cpu/ppc4xx/4xx_uart.c
@@ -98,14 +98,14 @@
 #define UDIV_SUBTRACT	0
 #define UART0_SDR	sdr_uart0
 #define UART1_SDR	sdr_uart1
-#if defined(CONFIG_440EP) || defined(CONFIG_440EPx) || \
-    defined(CONFIG_440GR) || defined(CONFIG_440GRx) || \
-    defined(CONFIG_440SP) || defined(CONFIG_440SPe) || \
+#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
+    defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
+    defined(CONFIG_440SP) || defined(CONFIG_440SPE) || \
     defined(CONFIG_460EX) || defined(CONFIG_460GT)
 #define UART2_SDR	sdr_uart2
 #endif
-#if defined(CONFIG_440EP) || defined(CONFIG_440EPx) || \
-    defined(CONFIG_440GR) || defined(CONFIG_440GRx) || \
+#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
+    defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
     defined(CONFIG_460EX) || defined(CONFIG_460GT)
 #define UART3_SDR	sdr_uart3
 #endif