Apply suggestion from @weebl2000

Co-authored-by: Wessel <wessel@weebl.me>

variants/muziworks_r1_neo/target.h

@@ -18,5 +18,5 @@ extern MomentaryButton user_btn;
 bool radio_init();
 uint32_t radio_get_rng_seed();
 void radio_set_params(float freq, float bw, uint8_t sf, uint8_t cr);
-void radio_set_tx_power(uint8_t dbm);
+void radio_set_tx_power(int8_t dbm);
 mesh::LocalIdentity radio_new_identity();