sh: only add -mno-fdpic if the compiler supports it

Not all SuperH toolchains support -mno-fdpic.  Chances are good that if
the flag doesn't work, it isn't defaulting to the FDPIC ABI, so the flag
isn't needed.  So only add it if it is actually supported.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

arch/sh/cpu/sh2/config.mk

@@ -24,10 +24,11 @@
 ENDIANNESS += -EB
 
 ifdef CONFIG_SH2A
-PLATFORM_CPPFLAGS += -m2a -m2a-nofpu -mb -mno-fdpic -ffreestanding
+PLATFORM_CPPFLAGS += -m2a -m2a-nofpu -mb -ffreestanding
 else # SH2
 PLATFORM_CPPFLAGS += -m3e -mb
 endif
+PLATFORM_CPPFLAGS += $(call cc-option,-mno-fdpic)
 
 PLATFORM_RELFLAGS += -ffixed-r13
 PLATFORM_LDFLAGS += $(ENDIANNESS)