scripts/spelling.txt: add misspelled words for check

misspelled words for check:-
 chcek
 chck
 cehck

I myself did these spell mistakes in changelog for patches, Thus
suggesting to add in spelling.txt, so that checkpatch.pl warns it
earlier.  References:-

./arch/powerpc/kernel/exceptions-64e.S:456: . . . make sure you chcek
https://lkml.org/lkml/2015/6/25/289
./arch/x86/mm/pageattr.c:1368: * No need to cehck in that case

[akpm@linux-foundation.org: add whcih->which, whcih I always get wrong]
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/spelling.txt

@@ -187,6 +187,7 @@ capatibilities||capabilities
 carefuly||carefully
 cariage||carriage
 catagory||category
+cehck||check
 challange||challenge
 challanges||challenges
 chanell||channel
@@ -199,6 +200,8 @@ charactor||character
 charater||character
 charaters||characters
 charcter||character
+chcek||check
+chck||check
 checksuming||checksumming
 childern||children
 childs||children
@@ -1028,6 +1031,7 @@ visiters||visitors
 vitual||virtual
 wating||waiting
 whataver||whatever
+whcih||which
 whenver||whenever
 wheter||whether
 whe||when