i2c: lpi2c: use readl_poll_timeout() for register polling

Replaces polling loops with the readl_poll_timeout() helper macro.

Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Carlos Song <carlos.song@nxp.com>
Tested-by: Primoz Fiser <primoz.fiser@norik.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250718133429.67219-2-francesco@dolcini.it