initramfs: prevent initramfs printk message being split by messages from other code.

initramfs uses printk without a linefeed, then does some work, then uses
printk to finish the message off.  However if some other code does a
printk in between, then the messages get mixed together.  Better for each
message to be an independent line...

Example of problem that this fixes:

    checking if image is initramfs...<7>Switched to high resolution mode on CPU 1
    Switched to high resolution mode on CPU 0
    it is

Signed-off-by: Simon Kitching <skitching@apache.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>