Move ARCH_* from board/Kconfig to cpu or soc Kconfig.

CONFIG_ARCH is a property of the cpu or soc rather than a property of the
board. Hence, move ARCH_* from every single board to respective cpu or soc
Kconfigs. Also update abuild to ignore ARCH_ from mainboards.

Change-Id: I6ec1206de5a20601c32d001a384a47f46e6ce479
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: http://review.coreboot.org/5570
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Move redundant Makefile rules from arch to top level.

Remove all the common Makefile rules like coreboot.pre, coreboot.pre1 and others
from arch level Makefile.inc to top level Makefile.inc.
Also, organize Makefile.inc at arch level into per-stage rules and variables.

Change-Id: I7dc5b2d31c959b55bb92d9c7811427c4dada1db5
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: http://review.coreboot.org/5571
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
build: allow building crossgcc when .config exists

Under some circumstances the coreboot toolchain test prevented
building crossgcc, which is counter-productive: If a .config file
exists but no suitable .xcompile.

Don't assume anything about the tree when building crossgcc or
crosstools targets.

Change-Id: I4d6e7a88908dc967342daf30df0fcbcc269ae63d
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/5584
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Martin Roth <martin.roth@se-eng.com>