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/post/cpu/ppc4xx/uart.c b/post/cpu/ppc4xx/uart.c
index 27cfb91..1a57c3d 100644
--- a/post/cpu/ppc4xx/uart.c
+++ b/post/cpu/ppc4xx/uart.c
@@ -79,13 +79,13 @@
 #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)
 #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)
 #define UART3_SDR	sdr_uart3
 #endif
 #define MFREG(a, d)	mfsdr(a, d)