pxafb: un-nest pxafb_parse_options() to cleanup the coding style issue

pxafb_parse_options() has very long lines exceeding far beyond 80 characters,
which makes the function looks bad.  Un-nest it into smaller functions and use
a temporary string for only what has been overridden instead of the whole
dev_info() message to reduce the line a bit more.

Signed-off-by: eric miao <eric.miao@marvell.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>