typo fixes

Most of these fixes were already submitted for old kernel versions, and were
approved, but for some reason they never made it into the releases.

Because this is a consolidation of a couple old missed patches, it touches both
Kconfigs and documentation texts.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

net/9p/Kconfig

@@ -27,5 +27,5 @@ config NET_9P_DEBUG
 	bool "Debug information"
 	depends on NET_9P
 	help
-	  Say Y if you want the 9P subsistem to log debug information.
+	  Say Y if you want the 9P subsystem to log debug information.
 

net/ipv4/Kconfig

@@ -560,7 +560,7 @@ config TCP_CONG_ILLINOIS
 	depends on EXPERIMENTAL
 	default n
 	---help---
-	TCP-Illinois is a sender-side modificatio of TCP Reno for
+	TCP-Illinois is a sender-side modification of TCP Reno for
 	high speed long delay links. It uses round-trip-time to
 	adjust the alpha and beta parameters to achieve a higher average
 	throughput and maintain fairness.