target/device/Soekris/net4521/linux.mk is missing an endif for
the first if statement
target/device/Soekris/Makefile.in needs to set TARGETS before
including linux.mk since the file checks the TARGETS variables
Currently each board is dumping all of its config options regardless of
whether we are even on the right architecture or not (this is due to
outright sourcing of the configs at the upper level..). Dependency
resolution either needs to be done there, or at the board-specific level.