rename files acc_ramp.* -> acc.c*

With upcoming next commit, the file will contain far more code that
simply ramping, so rename it to be more generic.

Change-Id: I8c368ab87e264439dea4ccf556821a44664cdbb0
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index a8b495f..cfed1f8 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -29,7 +29,7 @@
 #include <osmocom/gsm/protocol/gsm_12_21.h>
 #include <osmocom/abis/e1_input.h>
 #include <osmocom/bsc/meas_rep.h>
-#include <osmocom/bsc/acc_ramp.h>
+#include <osmocom/bsc/acc.h>
 #include <osmocom/bsc/neighbor_ident.h>
 #include <osmocom/bsc/osmux.h>