bcma: fix implicit use of export.h contents

Fix in advance, or we will get things like this:

drivers/bcma/core.c:20: warning: data definition has no type or storage class
drivers/bcma/core.c:20: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
drivers/bcma/core.c:20: warning: parameter names (without types) in function declaration

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>