Fix following warnings:

WARNING: drivers/tty/serial/built-in.o(.text+0x7370): Section mismatch in reference from the function grlib_apbuart_configure() to the variable .init.data:apbuart_match
The function grlib_apbuart_configure() references
the variable __initdata apbuart_match.
This is often because grlib_apbuart_configure lacks a __initdata
annotation or the annotation of apbuart_match is wrong.

+ 3 more warnings like this.

There is no guarantee that grlib_apbuart_of_driver.of_match_table
is only used at __init time - so drop the __initdata annotation.

grlib_apbuart_configure() is only used during __init so add __init
to this method too.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Hellstrom <daniel@gaisler.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>