powerpc: P2020: Remove macro CONFIG_P2020

Replace CONFIG_P2020 with ARCH_P2020 in Kconfig and clean up
existing macros.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/include/asm/config_mpc85xx.h b/arch/powerpc/include/asm/config_mpc85xx.h
index 6874b54..814a9fb 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -295,7 +295,7 @@
 #define CONFIG_SYS_FSL_ERRATUM_A004508
 #define CONFIG_SYS_FSL_ERRATUM_A005125
 
-#elif defined(CONFIG_P2020)
+#elif defined(CONFIG_ARCH_P2020)
 #define CONFIG_MAX_CPUS			2
 #define CONFIG_SYS_FSL_NUM_LAWS		12
 #define CONFIG_SYS_PPC_E500_DEBUG_TLB	2
diff --git a/arch/powerpc/include/asm/fsl_law.h b/arch/powerpc/include/asm/fsl_law.h
index 4e5ea5f..eee78c8 100644
--- a/arch/powerpc/include/asm/fsl_law.h
+++ b/arch/powerpc/include/asm/fsl_law.h
@@ -85,7 +85,7 @@
 #if defined(CONFIG_ARCH_BSC9131) || defined(CONFIG_ARCH_BSC9132)
 	LAW_TRGT_IF_OCN_DSP = 0x03,
 #else
-#if !defined(CONFIG_ARCH_MPC8572) && !defined(CONFIG_P2020)
+#if !defined(CONFIG_ARCH_MPC8572) && !defined(CONFIG_ARCH_P2020)
 	LAW_TRGT_IF_PCIE_3 = 0x03,
 #endif
 #endif
@@ -121,7 +121,7 @@
 #define LAW_TRGT_IF_PCIE_1	LAW_TRGT_IF_PCI
 #endif
 
-#if defined(CONFIG_ARCH_MPC8572) || defined(CONFIG_P2020)
+#if defined(CONFIG_ARCH_MPC8572) || defined(CONFIG_ARCH_P2020)
 #define LAW_TRGT_IF_PCIE_3	LAW_TRGT_IF_PCI
 #endif
 #endif /* CONFIG_FSL_CORENET */
diff --git a/arch/powerpc/include/asm/immap_85xx.h b/arch/powerpc/include/asm/immap_85xx.h
index f8a6a78..ba0faa8 100644
--- a/arch/powerpc/include/asm/immap_85xx.h
+++ b/arch/powerpc/include/asm/immap_85xx.h
@@ -2940,7 +2940,7 @@
 #define CONFIG_SYS_MPC85xx_PCIX2_OFFSET		0x9000
 #define CONFIG_SYS_MPC85xx_PCIE1_OFFSET         0xa000
 #define CONFIG_SYS_MPC85xx_PCIE2_OFFSET         0x9000
-#if defined(CONFIG_ARCH_MPC8572) || defined(CONFIG_P2020)
+#if defined(CONFIG_ARCH_MPC8572) || defined(CONFIG_ARCH_P2020)
 #define CONFIG_SYS_MPC85xx_PCIE3_OFFSET         0x8000
 #else
 #define CONFIG_SYS_MPC85xx_PCIE3_OFFSET         0xb000