Fix configuration of initial_(m)cs

Properly clip initial_(m)cs values to be lower-equal than maximum
configured.

Regarding initial_mcs, use values provided by BTS, which were not used
before.

Change-Id: Ifc6bc7c2734d1ae404adc2497afec5366e4f9e50
diff --git a/src/bts.h b/src/bts.h
index 9f2f898..4d5d0df 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -115,10 +115,11 @@
 	uint8_t initial_cs_dl, initial_cs_ul;
 	uint8_t initial_mcs_dl, initial_mcs_ul;
 	struct { /* Config Values set by VTY */
+		bool force_initial_cs;	/* false=use from BTS true=use from VTY */
+		bool force_initial_mcs;	/* false=use from BTS true=use from VTY */
 		uint8_t max_cs_dl, max_cs_ul;
 		uint8_t max_mcs_dl, max_mcs_ul;
 	} vty;
-	uint8_t force_cs;	/* 0=use from BTS 1=use from VTY */
 	uint16_t force_llc_lifetime; /* overrides lifetime from SGSN */
 	uint32_t llc_discard_csec;
 	uint32_t llc_idle_ack_csec;