powerpc/ps3: Make real stack frames for LV1 hcalls

The PS3 hcall assembly code makes ad-hoc stack frames that don't have
a back-chain pointer or meet other requirements like minimum frame size.
This probably confuses stack unwinders. Give all hcalls a real stack
frame.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Geoff Levand <geoff@infradead.org>
[mpe: Add missing \ in LV1_2_IN_4_OUT]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231227072405.63751-4-npiggin@gmail.com