ppc/pnv: powerpc_excp: Do not discard HDECR exception when entering power-saving...

ppc/pnv: powerpc_excp: Do not discard HDECR exception when entering power-saving mode

The Hypervisor Decrementer exception should not be generated while the
CPU is in power-saving mode (see cpu_ppc_hdecr_excp()). However,
discarding the exception before entering the power-saving mode is
wrong since we would loose a previously generated HDEC.

Fixes: 4b236b621bf0 ("ppc: Initial HDEC support")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20210809134547.689560-4-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>