usr/Kconfig: fix typos of "its"

usr/Kconfig: fix typos of "its"

Use "Its" or "its" for possessive instead of "it's" (contraction
for "it is").

Link: https://lkml.kernel.org/r/20231210053429.23146-1-rdunlap@infradead.org
Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initram compression algorithm")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Acked-by: "Francisco Blas Izquierdo Riera (klondike)" <klondike@klondike.es>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>