s390/ftrace: Remove unused ftrace_plt_template*

Unused since commit b860b934 ("s390/ftrace: remove dead code").
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/ftrace.h

@@ -18,7 +18,5 @@ extern const char ftrace_shared_hotpatch_trampoline_br[];
 extern const char ftrace_shared_hotpatch_trampoline_br_end[];
 extern const char ftrace_shared_hotpatch_trampoline_exrl[];
 extern const char ftrace_shared_hotpatch_trampoline_exrl_end[];
-extern const char ftrace_plt_template[];
-extern const char ftrace_plt_template_end[];
 
 #endif /* _FTRACE_H */