next-checks: check cargo doc for all rf-a platforms

`cargo doc` is not a platform independent test in the case
of the rf-a repository..
For the rest of the crates, `cargo doc` should still be a platform
independent test.

 * Run `cargo doc` on rf-a for all platforms. Remove rf-a's
   `cargo doc` tests from the platform independent testing scripts
   and add it to the next-checks (static checks) scripts.

Change-Id: Ib605d674bff2490f84837a1c565dbd333fa5657b
Signed-off-by: Tomás González <tomasagustin.gonzalezorlando@arm.com>
diff --git a/script/next-checks/next-checks.sh b/script/next-checks/next-checks.sh
index 633a2f4..56bd41b 100755
--- a/script/next-checks/next-checks.sh
+++ b/script/next-checks/next-checks.sh
@@ -88,6 +88,18 @@
 fi
 echo
 
+# Check documentation with cargo doc
+
+"$CI_ROOT"/script/next-checks/next-checks-cargo-doc.sh .
+
+if [ "$?" != 0 ]; then
+  echo "cargo doc test: FAILURE"
+  ((ERROR_COUNT++))
+else
+  echo "cargo doc test: PASS"
+fi
+echo
+
 # Check lints with clippy
 
 "$CI_ROOT"/script/next-checks/next-checks-clippy.sh .