powerpc/32: Rearrange _switch to prepare for 32/64 merge

Change the order of some operations and change some register numbers in
preparation to merge 32-bit and 64-bit switch.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230606132447.315714-5-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2023-06-06 23:24:45 +10:00 • committed by Michael Ellerman
commit 6958ad05d5