hm0360: _set_pll(): guard against wide reads and silence unused-param warnings

* Mark all currently unused PLL parameters with (void) to remove
  -Wunused-parameter noise.
* After a successful read_reg(), reject any value > 0xFF and return
  -ERANGE.  Ensures only 8-bit data is written to PLL1CFG.

Author: RubenKelevra

sensors/hm0360.c

@@ -6,6 +6,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 #include "sccb.h"
 #include "xclk.h"
 #include "hm0360.h"
@@ -345,6 +346,14 @@ static int set_xclk(sensor_t *sensor, int timer, int xclk)
 
 static int _set_pll(sensor_t *sensor, int bypass, int multiplier, int sys_div, int root_2x, int pre_div, int seld5, int pclk_manual, int pclk_div)
 {
+    (void)bypass;
+    (void)multiplier;
+    (void)sys_div;
+    (void)root_2x;
+    (void)pre_div;
+    (void)seld5;
+    (void)pclk_manual;
+    (void)pclk_div;
     uint8_t value = 0;
     uint8_t pll_cfg = 0;
 
@@ -362,6 +371,14 @@ static int _set_pll(sensor_t *sensor, int bypass, int multiplier, int sys_div, i
     if (ret < 0) {
         return ret;
     }
+    if (ret > 0xFF) {
+        /*
+         * Guard against unexpected wide register values. If read_reg
+         * ever returns a 16-bit result, reject values that don't fit
+         * in a single byte to avoid truncation.
+         */
+        return -ERANGE;
+    }
 
     pll_cfg = (uint8_t)ret;
     return write_reg(sensor->slv_addr, PLL1CFG, (pll_cfg & 0xFC) | value);