ARM: 7521/1: Fix semihosting Kconfig text

It seems we were missing some text in the title for the
semihosting DEBUG_LL option. Add in the "/O" and fix up some
minor typos in the help text.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig.debug

@@ -356,15 +356,15 @@ choice
 		  is nothing connected to read from the DCC.
 
 	config DEBUG_SEMIHOSTING
-		bool "Kernel low-level debug output via semihosting I"
+		bool "Kernel low-level debug output via semihosting I/O"
 		help
 		  Semihosting enables code running on an ARM target to use
 		  the I/O facilities on a host debugger/emulator through a
-		  simple SVC calls. The host debugger or emulator must have
+		  simple SVC call. The host debugger or emulator must have
 		  semihosting enabled for the special svc call to be trapped
 		  otherwise the kernel will crash.
 
-		  This is known to work with OpenOCD, as wellas
+		  This is known to work with OpenOCD, as well as
 		  ARM's Fast Models, or any other controlling environment
 		  that implements semihosting.