selftests/powerpc: Remove Power9 copy_unaligned test

This is a test of the ISA 3.0 "copy" instruction. That instruction has
an L field, which if set to 1 specifies that "the instruction
identifies the beginning of a move group" (pp 858). That's also
referred to as "copy first" vs "copy".

In ISA 3.0B the copy instruction does not have an L field, and the
corresponding bit in the instruction must be set to 1.

This test is generating a "copy" instruction, not a "copy first", and
so on Power9 (which implements 3.0B), this results in an illegal
instruction.

So just drop the test entirely. We still have copy_first_unaligned to
test the "copy first" behaviour.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>