Dependency to meta-python

[dl9pf]

ERROR: Nothing RPROVIDES 'python-pyserial' (but /home/dl9pf/layerindexeval/tmp.GVNk7lptmM/layers-under-test/meta-96boards/recipes-bsp/burn-boot/burn-boot_git.bb RDEPENDS on or otherwise requires it)
NOTE: Runtime target 'python-pyserial' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['python-pyserial']

Not in README nor LAYERDEPENDS .

[fboudra]

@petegriffin fyi