selftests/powerpc: Revert Load Monitor Register Tests

Load monitored won't be supported in POWER9, so PPC_FEATURE2_ARCH_3_00
(in HWCAP2) will no longer imply Load monitor support.

These Load monitored tests are enabled by PPC_FEATURE2_ARCH_3_00 so
they are now bogus and need to be removed.

This reverts commit 16c19a2e ("selftests/powerpc: Load Monitor
Register Tests").

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