docs(coding-standard): Rework guidelines on the max line length

The coding guidelines it reworked to explain the recommended line
length and the enforced length in the static check.

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: Ia4e089566c7d84bfe1b24e018476974b9eb9cd97
diff --git a/docs/process/coding-standard.rst b/docs/process/coding-standard.rst
index 315d5f9..28800bf 100644
--- a/docs/process/coding-standard.rst
+++ b/docs/process/coding-standard.rst
@@ -52,8 +52,9 @@
   This will not be enforced, any function being longer should trigger a
   discussion during the review process.
 
-- A line must be <= 80 characters, except for string literals as it would make
-  any search for it more difficult.
+- The recommended maximum line length is 80 characters, except for string literals
+  as it would make any search for it more difficult. A maximum length of 100
+  characters is enforced by the coding guidelines static check.
 
 - A variable should not be longer than 31 characters.
 
@@ -66,7 +67,7 @@
 +==============+===================================+
 |   function   |     24 lines (not enforced)       |
 +--------------+-----------------------------------+
-|     line     |          80 characters            |
+|     line     |          100 characters           |
 +--------------+-----------------------------------+
 |  identifier  |          31 characters            |
 +--------------+-----------------------------------+