proc_fops: convert drivers/isdn/ to seq_file

Convert code away from ->read_proc/->write_proc interfaces.  Switch to
proc_create()/proc_create_data() which make addition of proc entries
reliable wrt NULL ->proc_fops, NULL ->data and so on.

Problem with ->read_proc et al is described here commit
786d7e1612 "Fix rmmod/read/write races in
/proc entries"

[akpm@linux-foundation.org: CONFIG_PROC_FS=n build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/isdn/hardware/avm/avmcard.h

@@ -556,8 +556,7 @@ u16  b1_send_message(struct capi_ctr *ctrl, struct sk_buff *skb);
 void b1_parse_version(avmctrl_info *card);
 irqreturn_t b1_interrupt(int interrupt, void *devptr);
 
-int b1ctl_read_proc(char *page, char **start, off_t off,
-        		int count, int *eof, struct capi_ctr *ctrl);
+extern const struct file_operations b1ctl_proc_fops;
 
 avmcard_dmainfo *avmcard_dma_alloc(char *name, struct pci_dev *,
 				   long rsize, long ssize);
@@ -577,7 +576,6 @@ void b1dma_register_appl(struct capi_ctr *ctrl,
 				capi_register_params *rp);
 void b1dma_release_appl(struct capi_ctr *ctrl, u16 appl);
 u16  b1dma_send_message(struct capi_ctr *ctrl, struct sk_buff *skb);
-int b1dmactl_read_proc(char *page, char **start, off_t off,
-        		int count, int *eof, struct capi_ctr *ctrl);
+extern const struct file_operations b1dmactl_proc_fops;
 
 #endif /* _AVMCARD_H_ */