fbcon: logo: disable logo at boot

Add logo.nologo kernel boot option to disable the logo in order to provide
more screen space for kernel messages; especially useful when debugging and
screen space is more critical.

newport_con driver changes are untested.

[akpm@linux-foundation.org: cleanups, coding-style fixes]
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>