powerpc: mpc8260: consolidate CONFIG_MPC8260 and CONFIG_8260

Before this commit, CONFIG_MPC8260 and CONFIG_8260
were used mixed-up.

All boards with mpc8260 cpu defined both of them:
  - CONFIG_MPC8260 was defined in board config headers
      and include/common.h
  - CONFIG_8260 was defined arch/powerpc/cpu/mpc8260/config.mk

We do not need to have both of them.
This commit keeps only CONFIG_MPC8260.

This commit does:
 - Delete CONFIG_8260 and CONFIG_MPC8260 definition
   in config headers and include/common.h
 - Rename CONFIG_8260 to CONFIG_MPC8260
    in arch/powerpc/cpu/mpc8260/config.mk.
 - Rename #ifdef CONFIG_8260 to #ifdef CONFIG_MPC8260

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Wolfgang Denk <wd@denx.de>
diff --git a/arch/powerpc/lib/board.c b/arch/powerpc/lib/board.c
index 13d761c..f86c6f3 100644
--- a/arch/powerpc/lib/board.c
+++ b/arch/powerpc/lib/board.c
@@ -277,10 +277,10 @@
 	serial_init,
 	console_init_f,
 	display_options,
-#if defined(CONFIG_8260)
+#if defined(CONFIG_MPC8260)
 	prt_8260_rsr,
 	prt_8260_clks,
-#endif /* CONFIG_8260 */
+#endif /* CONFIG_MPC8260 */
 #if defined(CONFIG_MPC83xx)
 	prt_83xx_rsr,
 #endif
@@ -504,7 +504,7 @@
 	bd->bi_sramsize = CONFIG_SYS_SRAM_SIZE;		/* size  of SRAM */
 #endif
 
-#if defined(CONFIG_8xx) || defined(CONFIG_8260) || defined(CONFIG_5xx) || \
+#if defined(CONFIG_8xx) || defined(CONFIG_MPC8260) || defined(CONFIG_5xx) || \
     defined(CONFIG_E500) || defined(CONFIG_MPC86xx)
 	bd->bi_immr_base = CONFIG_SYS_IMMR;	/* base  of IMMR register     */
 #endif