powerpc: mpc8540: Remove macro CONFIG_MPC8540

Replace CONFIG_MPC8540 with ARCH_MPC8540 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 be1ab4a..7f9b2d9 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -44,7 +44,7 @@
 #define CONFIG_SYS_FSL_ERRATUM_A004508
 #define CONFIG_SYS_FSL_ERRATUM_A005125
 
-#elif defined(CONFIG_MPC8540)
+#elif defined(CONFIG_ARCH_MPC8540)
 #define CONFIG_MAX_CPUS			1
 #define CONFIG_SYS_FSL_NUM_LAWS		8
 #define CONFIG_SYS_FSL_DDRC_GEN1
diff --git a/arch/powerpc/include/asm/fsl_lbc.h b/arch/powerpc/include/asm/fsl_lbc.h
index 402edd7..6e4b087 100644
--- a/arch/powerpc/include/asm/fsl_lbc.h
+++ b/arch/powerpc/include/asm/fsl_lbc.h
@@ -325,7 +325,7 @@
  */
 #define LCRR_CLKDIV			0x0000001F
 #define LCRR_CLKDIV_SHIFT		0
-#if defined(CONFIG_MPC83xx) || defined (CONFIG_MPC8540) || \
+#if defined(CONFIG_MPC83xx) || defined(CONFIG_ARCH_MPC8540) || \
     defined(CONFIG_MPC8541) || defined (CONFIG_MPC8555) || \
     defined(CONFIG_MPC8560)
 #define LCRR_CLKDIV_2			0x00000002
diff --git a/arch/powerpc/include/asm/immap_85xx.h b/arch/powerpc/include/asm/immap_85xx.h
index 1ae5af1..2e959dd 100644
--- a/arch/powerpc/include/asm/immap_85xx.h
+++ b/arch/powerpc/include/asm/immap_85xx.h
@@ -124,7 +124,7 @@
 	u8	res[4096 - 1 * sizeof(struct fsl_i2c_base)];
 } ccsr_i2c_t;
 
-#if defined(CONFIG_MPC8540) || \
+#if defined(CONFIG_ARCH_MPC8540) || \
 	defined(CONFIG_MPC8541) || \
 	defined(CONFIG_ARCH_MPC8548) || \
 	defined(CONFIG_MPC8555)