gsm0808: Add CSFB indication IE to BSSMAP CLEAR COMMAND

When a call that was established in a CSFB context ends the CLEAR
COMMAND that is send from the BSC to the MSC should contain a CSFB
indication IE, which consists of just the IE byte itsslef. This
additional IE tells the BSC to include other CSFB related IEs into the
RR Release message.

Change-Id: Id8a75e1da2d5f520064666e4ee413d1c91da6ae3
Related: OS#3778
diff --git a/include/osmocom/gsm/gsm0808.h b/include/osmocom/gsm/gsm0808.h
index 6d14e13..35e7a8e 100644
--- a/include/osmocom/gsm/gsm0808.h
+++ b/include/osmocom/gsm/gsm0808.h
@@ -49,6 +49,7 @@
 struct msgb *gsm0808_create_reset(void);
 struct msgb *gsm0808_create_reset_ack(void);
 struct msgb *gsm0808_create_clear_command(uint8_t cause);
+struct msgb *gsm0808_create_clear_command2(uint8_t cause, bool csfb_ind);
 struct msgb *gsm0808_create_clear_complete(void);
 struct msgb *gsm0808_create_cipher(const struct gsm0808_encrypt_info *ei,
 				   const uint8_t *cipher_response_mode);