spi: switch to managed controller allocation (part 3/3)

Johan Hovold <johan@kernel.org> says:

In preparation for fixing the SPI controller API so that it no longer
drops a reference when deregistering (non-managed) controllers (cf.
[1]), this series converts drivers using managed registration to also
use managed allocation.

Included is also a related cleanup of a lp8841-rtc.

This leaves us with 18 drivers using non-managed allocation, which is
few enough to be able to fix the API in tree-wide change.

Johan

[1] https://lore.kernel.org/lkml/20260325145319.1132072-1-johan@kernel.org/

Link: https://patch.msgid.link/20260511150408.796155-1-johan@kernel.org