tree ef92f75a73693017a4bc42e690eec2b0618d48cc
parent a7d0c879450cca60e187afd279e28f270e7c3287
author Masahiro Yamada <yamada.m@jp.panasonic.com> 1403615452 +0900
committer Tom Rini <trini@ti.com> 1404776554 -0400

build: define CPU only when arch/${ARCH}/cpu/${CPU} exists

The directory arch/${ARCH}/cpu/${CPU} does not exist
in avr32, blackfin, microblaze, nios2, openrisc, sandbox, x86.

These architectures have only one CPU type.
Defining CPU should not be required for such architectures.

This commit allows cpu field (= the 3rd field of boards.cfg)
to be kept blank.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Andreas Bießmann <andreas.devel@googlemail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Sonic Zhang <sonic.zhang@analog.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Thomas Chou <thomas@wytron.com.tw>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>