Fix get/setDrvPct declarations

Marlin/dac_mcp4728.cpp

 /**
  * Returns DAC values as a 0-100 percentage of drive strength
  */
-uint16_t mcp4728_getDrvPct(uint8_t channel) { return uint16_t(100.0 * mcp4728_values[channel] / (DAC_STEPPER_MAX) + 0.5); }
+uint8_t mcp4728_getDrvPct(uint8_t channel) { return uint8_t(100.0 * mcp4728_values[channel] / (DAC_STEPPER_MAX) + 0.5); }
 
 /**
  * Receives all Drive strengths as 0-100 percent values, updates
  * DAC Values array and calls fastwrite to update the DAC.
  */
-void mcp4728_setDrvPct(uint16_t pct[XYZE]) {
+void mcp4728_setDrvPct(uint8_t pct[XYZE]) {
   LOOP_XYZE(i) mcp4728_values[i] = 0.01 * pct[i] * (DAC_STEPPER_MAX);
   mcp4728_fastWrite();
 }

Marlin/dac_mcp4728.h

 uint16_t mcp4728_getValue(uint8_t channel);
 uint8_t mcp4728_fastWrite();
 uint8_t mcp4728_simpleCommand(byte simpleCommand);
-uint16_t mcp4728_getDrvPct(uint8_t channel);
-void mcp4728_setDrvPct(uint16_t pct[XYZE]);
+uint8_t mcp4728_getDrvPct(uint8_t channel);
+void mcp4728_setDrvPct(uint8_t pct[XYZE]);
 
 #endif
 #endif // DAC_MCP4728_H