ppc4xx: Big cleanup of PPC4xx defines

This patch cleans up multiple issues of the 4xx register (mostly
DCR, SDR, CPR, etc) definitions:

- Change lower case defines to upper case (plb4_acr -> PLB4_ACR)
- Change the defines to better match the names from the
  user's manuals (e.g. cprpllc -> CPR0_PLLC)
- Removal of some unused defines

Please test this patch intensive on your PPC4xx platform. Even though
I tried not to break anything and tested successfully on multiple
4xx AMCC platforms, testing on custom platforms is recommended.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/cpu/ppc4xx/sdram.c b/cpu/ppc4xx/sdram.c
index 4365df9..5a3336e 100644
--- a/cpu/ppc4xx/sdram.c
+++ b/cpu/ppc4xx/sdram.c
@@ -375,8 +375,8 @@
 	/*
 	 * Soft-reset SDRAM controller.
 	 */
-	mtsdr(sdr_srst, SDR0_SRST_DMC);
-	mtsdr(sdr_srst, 0x00000000);
+	mtsdr(SDR0_SRST, SDR0_SRST_DMC);
+	mtsdr(SDR0_SRST, 0x00000000);
 #endif
 
 	for (i=0; i<N_MB0CF; i++) {