serial: max310x: simplify max310x_update_best_err()

serial: max310x: simplify max310x_update_best_err()

besterr was defined as a signed type was to make sure that the first call
to max310x_update_best_err() would always set besterr. Also there is no
need for it to be a long. By changing its type to unsigned int and initial
value to UINT_MAX, max310x_update_best_err() can be simplified and be more
efficient while achieving the same initial result.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260417-max310x-2-v1-2-b424e105ecac@dimonoff.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>