lib/linear_ranges: fix repeated words & one typo

lib/linear_ranges: fix repeated words & one typo

Change "which which" to "for which" in 3 places.
Change "ranges" to possessive "range's" in 1 place.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20201221040610.12809-1-rdunlap@infradead.org
Signed-off-by: Mark Brown <broonie@kernel.org>