[coreboot] [PATCH]Less noisy Makefile format

[Patrick Georgi]

Hi,

attached patch uses the gnu make .SILENT: mechanism instead of requiring
$(Q) in front of every silent line.

make V=1 or make Q="" still make make noisy again.

I checked operation by building a couple of boards, and looked over the
diff, but the removal of the $(Q)s was an automatic one, and I might
have missed some mistake introduced by improper tool use

Signed-off-by: Patrick Georgi