[ARM] Fix decompressor serial IO to give CRLF not LFCR

As per the corresponding change to the serial drivers, arrange
for ARM decompressors to give CRLF.  Move the common putstr code
into misc.c such that machines only need to supply "putc" and
"flush" functions.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>