The calculated values for the minlen and maxlen fields, which were
rounded to multiples of 2 and clamped to a valid range, were left
unused. Use them in the calculation of the register value rather than
using the raw input minlen and maxlen.
This fixes the following warning with a W=1 build:
drivers/media/rc/img-ir/img-ir-hw.c In function ‘img_ir_free_timing’:
drivers/media/rc/img-ir/img-ir-hw.c +228 :23: warning: variable ‘maxlen’ set but not used [-Wunused-but-set-variable]
drivers/media/rc/img-ir/img-ir-hw.c +228 :15: warning: variable ‘minlen’ set but not used [-Wunused-but-set-variable]