btif: standardize types, #ifs

Use standard types everywhere.
Use standard style for #if statements:
 - #if (VAR_NAME == TRUE)
 - #if (VAR_NAME1 == TRUE && VAR_NAME2 == TRUE)
Use __func__ instead of __FUNCTION__

Change-Id: Ic29d1d0b32c3ca9953752a4e5da6c28f45ec8895