armhf: Replace u-boot package with specific variant

The u-boot metapackage has been dropped for armhf architecture. Replace it with a specific variant such as u-boot-sunxi, u-boot-rpi, or u-boot-omap.

Closes: #208 (closed).

Tests:

• Successfully build unstable images for the following targets:
  • a20-olinuxino-lime
  • a20-olinuxino-lime2
  • a20-olinuxino-micro
  • banana-pro
  • beaglebone
  • cubieboard2
  • cubietruck
  • lamobo-r1
  • orange-pi-zero
  • pcduino3
  • raspberry2
  • raspberry3
  • raspberry3-b-plus

Signed-off-by: James Valleroy jvalleroy@mailbox.org

Looks good. Merged based on the testing already done.

closed