.gitignore: add output files for various make targets

- Ignore output files for the new utilities amdfwtool and intelvbttool
- Ignore xml files for 'make what-jenkins-does'
- Ignore build files from libpayload's 'make install'

Change-Id: Ie4f1c9bf7dc597f7600c8bda0c6fad5f40acf7f8
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12512
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed