MIPS: Drop unreferenced CONFIG_* defines

The following config symbols are only defined once and never referenced
anywhere else:

CONFIG_DBAU1X00
CONFIG_PB1X00

Most of them are config symbols named after the respective boards which
seems to have been a standard practice at some point.
Signed-off-by: NTuomas Tynkkynen <tuomas@tuxera.com>

include/configs/dbau1x00.h

@@ -12,7 +12,6 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
-#define CONFIG_DBAU1X00		1
 #define CONFIG_SOC_AU1X00	1  /* alchemy series cpu */
 
 #ifdef CONFIG_DBAU1000

include/configs/pb1x00.h

@@ -12,7 +12,6 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
-#define CONFIG_PB1X00		1
 #define CONFIG_SOC_AU1X00	1  /* alchemy series cpu */
 
 #ifdef CONFIG_PB1000

scripts/config_whitelist.txt

@@ -325,7 +325,6 @@ CONFIG_DA850_AM18X_EVM
 CONFIG_DA850_EVM_MAX_CPU_CLK
 CONFIG_DA8XX_GPIO
 CONFIG_DBAU1000
-CONFIG_DBAU1X00
 CONFIG_DBGU
 CONFIG_DBG_MONITOR
 CONFIG_DB_784MP_GP
@@ -1496,7 +1495,6 @@ CONFIG_PARAVIRT
 CONFIG_PB1000
 CONFIG_PB1100
 CONFIG_PB1500
-CONFIG_PB1X00
 CONFIG_PCA953X
 CONFIG_PCA9698
 CONFIG_PCI1