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/[e-mail]
Fixes: db2aa7fd15e8 ("initramfs: allow again choice of the embedded initram compression algorithm")
Signed-off-by: Randy Dunlap <[e-mail]>
Reviewed-by: Nicolas Schier <[e-mail]>
Acked-by: "Francisco Blas Izquierdo Riera (klondike)" <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Nathan Chancellor <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

usr/Kconfig

···
 	bool "LZO"
 	depends on RD_LZO
 	help
-	  It's compression ratio is the second poorest amongst the choices. The
-	  kernel size is about 10% bigger than gzip. Despite that, it's
-	  decompression speed is the second fastest and it's compression speed
+	  Its compression ratio is the second poorest amongst the choices. The
+	  kernel size is about 10% bigger than gzip. Despite that, its
+	  decompression speed is the second fastest and its compression speed
 	  is quite fast too.
 
 	  If you choose this, keep in mind that you may need to install the lzop