Documentation/kernel-parameters.txt: fix memmap= language

Clean up descriptions of memmap= boot options.

Add periods (full stops), drop commas, change "used" to "reserved" or
"marked".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andiry Xu <andiry.xu@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kernel-parameters.txt

@@ -1726,16 +1726,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			option description.
 
 	memmap=nn[KMG]@ss[KMG]
-			[KNL] Force usage of a specific region of memory
-			Region of memory to be used, from ss to ss+nn.
+			[KNL] Force usage of a specific region of memory.
+			Region of memory to be used is from ss to ss+nn.
 
 	memmap=nn[KMG]#ss[KMG]
 			[KNL,ACPI] Mark specific memory as ACPI data.
-			Region of memory to be used, from ss to ss+nn.
+			Region of memory to be marked is from ss to ss+nn.
 
 	memmap=nn[KMG]$ss[KMG]
 			[KNL,ACPI] Mark specific memory as reserved.
-			Region of memory to be used, from ss to ss+nn.
+			Region of memory to be reserved is from ss to ss+nn.
 			Example: Exclude memory from 0x18690000-0x1869ffff
 			         memmap=64K$0x18690000
 			         or