Revert "perf s390: Always build with -fPIC"

This one made x86 always build with -fPIC, when the intention was for
s390 to be built that way, due to a rebase mistake.
Reported-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
This reverts commit 1dc4ddf1.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile.config

@@ -43,7 +43,6 @@ ifeq ($(SRCARCH),x86)
     LIBUNWIND_LIBS = -lunwind-x86 -llzma -lunwind
   endif
   NO_PERF_REGS := 0
-  CFLAGS += -fPIC
 endif
 
 ifeq ($(SRCARCH),arm)