edge: Add methods for unified GPRS/EGPRS UL data block handling

The current rcv_data_block_acknowledged_gprs method is tightly
coupled to GPRS.

This commit adds variants of the involved methods that support
EGPRS and GPRS RLC encodings likewise.

Sponsored-by: On-Waves ehf
diff --git a/src/rlc.h b/src/rlc.h
index bc93c2d..f2acb98 100644
--- a/src/rlc.h
+++ b/src/rlc.h
@@ -86,6 +86,7 @@
 	/* block len of history */
 	uint8_t len;
 
+	struct gprs_rlc_ul_data_block_info block_info;
 	GprsCodingScheme cs;
 };