spi: rzv2m-csi: Leave readl_poll_timeout calls for last

spi: rzv2m-csi: Leave readl_poll_timeout calls for last

Both rzv2m_csi_sw_reset and rzv2m_csi_start_stop_operation
call into readl_poll_timeout upon a certain condition, and
return 0 otherwise.
Flip the logic to improve readability.

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230715010407.1751715-5-fabrizio.castro.jz@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>