Documentation: Describe our Coverity Scan integration

Change-Id: I0a2b68a4b4b54c7345280b252d624799316641b1
Signed-off-by: Patrick Georgi <patrick@coreboot.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62666
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

Documentation/infrastructure/builders.md

@@ -61,7 +61,7 @@ coreboot project has 3 active jenkins build machines.
 There are a number of builds handled by the coreboot jenkins builders,
 for a number of different projects - coreboot, flashrom, memtest86+,
 em100, etc.  Many of these have builders for their current master branch
-as well as gerrit and coverity builds.
+as well as Gerrit and [Coverity](coverity.md) builds.
 
 You can see all the builds here:
 [https://qa.coreboot.org/](https://qa.coreboot.org/)