Avoid assembler warnings from AArch64 constructor/destructor priorities.

Avoid assembler warnings from AArch64 constructor/destructor priorities.

Many GCC tests fail for AArch64 with current binutils because of
assembler warnings of the form "Warning: ignoring incorrect section
type for .init_array.00100".  The same issue was fixed for ARM in
r247015 by using SECTION_NOTYPE when creating those sections; this
patch applies the same fix to AArch64.

Tested with no regressions with cross to aarch64-linux-gnu.

	* config/aarch64/aarch64.c (aarch64_elf_asm_constructor)
	(aarch64_elf_asm_destructor): Pass SECTION_NOTYPE to get_section
	when creating .init_array and .fini_array sections with priority
	specified.

From-SVN: r253252