Makefile: define build result directories

Final build results (.elf, .debug, .map) are to be placed under
directory $(objcbfs), the default is:
   $(obj)/cbfs/$(CONFIG_CBFS_PREFIX)/

Intermediate build results (.o, .s, .S, .inc, .ld) that do not have
a clear one-to-one relation to a file under src/ are to be placed
under directory $(objgenerated), the default is:
   $(obj)/generated

Also defines implicit rules for final build results:

  .debug -> .elf and .map
  .elf -> .bin

Change-Id: I448c6b7c9a952e54170df42091d7db438025a795
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/858
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
2 files changed