sh: move CONFIG_{SH2, SH2A, SH3, SH4} to Kconfig

This commit moves CONFIG_SH2, CONFIG_SH2A, CONFIG_SH3, CONFIG_SH4
to Kconfig renaming into CONFIG_CPU_SH2, CONFIG_CPU_SH2A,
CONFIG_CPU_SH3, CONFIG_CPU_SH4, respectively because
arch/sh/Kconfig of Linux uses CONFIG_CPU_SH* convention.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/sh/cpu/sh4/config.mk b/arch/sh/cpu/sh4/config.mk
index 5773d4f..4fb2dc2 100644
--- a/arch/sh/cpu/sh4/config.mk
+++ b/arch/sh/cpu/sh4/config.mk
@@ -8,4 +8,4 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 #
-PLATFORM_CPPFLAGS += -DCONFIG_SH4 -m4-nofpu
+PLATFORM_CPPFLAGS += -m4-nofpu