x86/fpu: Add a pkru argument to copy_uabi_from_kernel_to_xstate().

x86/fpu: Add a pkru argument to copy_uabi_from_kernel_to_xstate().

commit 1c813ce0305571e1b2e4cc4acca451da9e6ad18f upstream

ptrace (through PTRACE_SETREGSET with NT_X86_XSTATE) ultimately calls
copy_uabi_from_kernel_to_xstate(). In preparation for eventually handling
PKRU in copy_uabi_to_xstate, pass in a pointer to the PKRU location.

Signed-off-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20221115230932.7126-3-khuey%40kylehuey.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>