isdn: eicon: fix old-style declarations

Modern C standards expect the '__inline__' keyword to come before the return
type in a declaration, and we get many warnings for this with "make W=1"
because the eicon driver has this in a header file:

eicon/divasmain.c:448:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/divasmain.c:453:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/divasmain.c:458:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/divasmain.c:463:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/divasmain.c:468:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/divasmain.c:473:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/platform.h:274:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]
eicon/platform.h:280:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]

A similar warning gets printed for the diva_os_register_io_port()
declaration, because 'register' is interpreted as a keyword instead
of a variable name:

In file included from eicon/diva_didd.c:21:0:
eicon/platform.h:206:1: error: 'register' is not at beginning of declaration [-Werror=old-style-declaration]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>