bcma: use static keyword for inline function declaration in bcma.h

bcma: use static keyword for inline function declaration in bcma.h

Just scratching an itch here, but it makes more sense to use the
static keyword if you think about how the compiler treats inline
functions.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
(cherry picked from commit 084455524f0d46dd210b4397898aff73579b97e8)