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/tests/handover/Makefile.am b/tests/handover/Makefile.am
index 661b3d2..87981d9 100644
--- a/tests/handover/Makefile.am
+++ b/tests/handover/Makefile.am
@@ -47,7 +47,7 @@
 	$(top_builddir)/src/osmo-bsc/abis_om2000.o \
 	$(top_builddir)/src/osmo-bsc/abis_om2000_vty.o \
 	$(top_builddir)/src/osmo-bsc/abis_rsl.o \
-	$(top_builddir)/src/osmo-bsc/acc_ramp.o \
+	$(top_builddir)/src/osmo-bsc/acc.o \
 	$(top_builddir)/src/osmo-bsc/arfcn_range_encode.o \
 	$(top_builddir)/src/osmo-bsc/assignment_fsm.o \
 	$(top_builddir)/src/osmo-bsc/bsc_ctrl_commands.o \