hamradio: baycom: fix old-style declaration

Modern C standards expect the '__inline__' keyword to come before the return
type in a declaration, and we get a warning for this with "make W=1":

drivers/net/hamradio/baycom_par.c:159:1: error: '__inline__' is not at beginning of declaration [-Werror=old-style-declaration]

For consistency with other drivers, I'm changing '__inline__' to 'inline'
at the same time.

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