linux-yocto/4.14: fix beaglebone configuration warnings
Backporting the following fixes from 4.18 to 4.14 to remove beaglebone
configuration warnings:
1fb0b0379fb5 beaglebone: Clean up the cfg file
4176e7ded8e1 beaglebone: Drop the needless unsetting of the kernel options
65c209da574d beaglebone: Drop the obsolete kernel options
Signed-off-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
