RISC-V: The object without priv spec attributes can be linked with any object.

RISC-V: The object without priv spec attributes can be linked with any object.

	bfd/
	* elfnn-riscv.c (riscv_merge_attributes): Add new boolean
	priv_may_conflict, in_priv_zero and out_priv_zero to decide whether
	the object can be linked according to it's priv attributes.  The object
	without any priv spec attributes can be linked with others.  If the first
	input object doesn't contain any priv attributes, then we need to copy
	the setting from the next input one.  Also report more detailed error
	messages to user.

	ld/
	* testsuite/ld-riscv-elf/attr-merge-priv-spec.d: Rename to
	attr-merge-priv-spec-01.d.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-c.s: Set priv spec
	to 1.11.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-d.s: Empty priv spec
	setting.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-02.d: New testcase.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-03.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-01.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-02.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-03.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-04.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-05.d: Likewise.
	* testsuite/ld-riscv-elf/attr-merge-priv-spec-failed-06.d: Likewise.
	* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.