Skip 'bx reg' on arm-linux

Skip 'bx reg' on arm-linux

In arm-tdep.c, arm_skip_stub is installed to gdbarch
skip_trampoline_code, but in arm-linux-tdep.c,
find_solib_trampoline_target is installed to skip_trampoline_code.
That means gdb configured for arm-linux target doesn't recognize some
arm specific trampolines or stubs.  Beside handling generic solib
trampoline, gdb for arm-linux target should be able to handle arm
specific trampolines.  This patch is to skip arm specific stubs, if
any, and as a fallback, skip the generic solib trampoline.

gdb:

2014-06-24  Yao Qi  <yao@codesourcery.com>

	* arm-linux-tdep.c (arm_linux_skip_trampoline_code): New.
	(arm_linux_init_abi): Set skip_trampoline_code with
	gdbarch_skip_trampoline_code instead of
	find_solib_trampoline_target.