enb,phy: reduce log level to info when RNTI isn't found

this can happen during user removal

2022-02-13T00:47:49.195816 [RRC    ] [I] Activity timer for rnti=0x50 expired after 80 ms
2022-02-13T00:47:49.195818 [GTPU   ] [I] Removing user - rnti=0x50 not found.
2022-02-13T00:47:49.195818 [STCK   ] [I] Bearers: No EPS bearer registered for rnti=0x50
2022-02-13T00:47:49.195827 [RRC    ] [I] Removed user rnti=0x50
2022-02-13T00:47:49.199697 [PHY    ] [E] [ 7234] Error setting grant for rnti=0x0, cc=0

2022-02-13T00:47:49.199698 [PHY0   ] [I] [ 7233] Failed setting UL grants. Some grant's RNTI does not exist.
2022-02-13T00:47:49.209172 [MAC    ] [I] [ 7242] User rnti=0x4f removed from MAC/PHY
2022-02-13T00:47:49.223248 [MAC    ] [I] [ 7256] User rnti=0x50 removed from MAC/PHY

srsenb/src/phy/phy_ue_db.cc

@@ -784,7 +784,7 @@ int phy_ue_db::set_ul_grant_available(uint32_t tti, const stack_interface_phy_lt
       // Check that eNb Cell/Carrier is active for the given RNTI
       if (_assert_active_enb_cc(rnti, enb_cc_idx) != SRSRAN_SUCCESS) {
         ret = SRSRAN_ERROR;
-        srslog::fetch_basic_logger("PHY").error("Error setting grant for rnti=0x%x, cc=%d\n", rnti, enb_cc_idx);
+        srslog::fetch_basic_logger("PHY").info("Error setting grant for rnti=0x%x, cc=%d", rnti, enb_cc_idx);
         continue;
       }
       // Rise Grant available flag