sparc: merge arch/sparc/cpu/*/config.mk to arch/sparc/config.mk

Remove arch/sparc/cpu/{leon2,leon3}/config.mk and move duplicated
defines of -fPIC to arch/sparc/config.mk.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Daniel Hellstrom <daniel@gaisler.com>

arch/sparc/config.mk

@@ -15,3 +15,5 @@ CONFIG_STANDALONE_LOAD_ADDR ?= 0x00000000 -L $(gcclibdir) \
 			       -T $(srctree)/examples/standalone/sparc.lds
 
 PLATFORM_CPPFLAGS += -D__sparc__
+
+PLATFORM_RELFLAGS += -fPIC

arch/sparc/cpu/leon2/config.mk

@@ -1,8 +0,0 @@
-#
-# (C) Copyright 2003
-# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
-#
-# SPDX-License-Identifier:	GPL-2.0+
-#
-
-PLATFORM_RELFLAGS += -fPIC

arch/sparc/cpu/leon3/config.mk

@@ -1,8 +0,0 @@
-#
-# (C) Copyright 2003
-# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
-#
-# SPDX-License-Identifier:	GPL-2.0+
-#
-
-PLATFORM_RELFLAGS += -fPIC