Fix minor bug

SRS_API was used instead of SRSRAN_API. Did not seem to have major
consequences.

lib/include/srsran/phy/phch/npbch.h

@@ -49,7 +49,7 @@ typedef struct {
  *
  *  Reference: 3GPP TS 36.211 version 13.2.0 Release 13 Sec. 10.2.4
  */
-typedef struct SRS_API {
+typedef struct SRSRAN_API {
   srsran_nbiot_cell_t cell;
 
   uint32_t frame_idx;