Remove markdown files from coding style check

All markdown (.md) files in the root directory of the repository and
all the files inside the 'docs' directory have been removed from
ROOT_DIRS_TO_CHECK in the Makefile in order not to perform the coding
style check on them.

Change-Id: Iac397b44f95cbcdb9a52cc20bf69998c394ac00a

Makefile

@@ -112,10 +112,10 @@ CHECK_IGNORE		:=	--ignore COMPLEX_MACRO \
 				--ignore GIT_COMMIT_ID
 CHECKPATCH_ARGS		:=	--no-tree --no-signoff ${CHECK_IGNORE}
 CHECKCODE_ARGS		:=	--no-patch --no-tree --no-signoff ${CHECK_IGNORE}
-# Do not check the coding style on C library files
+# Do not check the coding style on C library files or documentation files
 INCLUDE_DIRS_TO_CHECK	:=	$(sort $(filter-out include/stdlib, $(wildcard include/*)))
 LIB_DIRS_TO_CHECK	:=	$(sort $(filter-out lib/stdlib, $(wildcard lib/*)))
-ROOT_DIRS_TO_CHECK	:=	$(sort $(filter-out lib include, $(wildcard *)))
+ROOT_DIRS_TO_CHECK	:=	$(sort $(filter-out lib include docs %.md, $(wildcard *)))
 CHECK_PATHS		:=	${ROOT_DIRS_TO_CHECK} ${INCLUDE_DIRS_TO_CHECK} ${LIB_DIRS_TO_CHECK}