Fix ARM compiler warning for microlib

- Remove the --library_type=micorlib from c/cxx configuration.

Author: rajkan01

tools/toolchains/arm.py

@@ -581,10 +581,6 @@ def __init__(self, target, *args, **kwargs):
                 self.flags['common'].append("-D__MICROLIB")
             if "--library_type=microlib" not in self.flags['ld']:
                 self.flags['ld'].append("--library_type=microlib")
-            if "-Wl,--library_type=microlib" not in self.flags['c']:
-                self.flags['c'].append("-Wl,--library_type=microlib")
-            if "-Wl,--library_type=microlib" not in self.flags['cxx']:
-                self.flags['cxx'].append("-Wl,--library_type=microlib")
             if "--library_type=microlib" not in self.flags['asm']:
                 self.flags['asm'].append("--library_type=microlib")