ea975dc Revert "uboot4extlinux-sunxi: .install: make u-boot image path configurable"

Authored and Committed by Denis 'GNUtoo' Carikli a month ago
    Revert "uboot4extlinux-sunxi: .install: make u-boot image path configurable"
    
    This commit was accidentally pushed to master instead of
    a branch.
    
    This reverts commit 1f2f68301569e4918d2d1da122ff241f93561ab8.