bug fix pic:elf do not generate unwind table

modlib_read: Read 64 bytes from offset 192665
modlib_symvalue: ERROR: SHN_UNDEF: Exported symbol "__gnu_Unwind_Find_exidx" not found
modlib_relocate: ERROR: Section 2 reloc 12: Failed to get value of symbol[246]: -2
elf_loadbinary: Failed to bind symbols program binary: -2
builtin_loadbinary: Loading file: /pic/hello

Signed-off-by: anjiahao <anjiahao@xiaomi.com>

Author: anjiahao1

arch/arm/src/common/Toolchain.defs

@@ -554,8 +554,8 @@ CXXELFFLAGS = $(CXXFLAGS)-fvisibility=hidden -mlong-calls
 
 ifeq ($(CONFIG_PIC),y)
   CFLAGS += --fixed-r10
-  CELFFLAGS += $(PICFLAGS) -mpic-register=r10
-  CXXELFFLAGS += $(PICFLAGS) -mpic-register=r10
+  CELFFLAGS += $(PICFLAGS) -mpic-register=r10 -fno-unwind-tables -fno-asynchronous-unwind-tables
+  CXXELFFLAGS += $(PICFLAGS) -mpic-register=r10 -fno-unwind-tables -fno-asynchronous-unwind-tables
 
   # Generate an executable elf, need to ignore undefined symbols
   LDELFFLAGS += --unresolved-symbols=ignore-in-object-files --emit-relocs