ccs811: add setEnv variant with float arguments

include/driver/ccs811.h

@@ -31,6 +31,7 @@ class CCS811 {
 		void setMode(unsigned char mode);
 		void read();
 		void setEnv(unsigned char humi, unsigned char humi_fraction, unsigned char temp, unsigned char temp_fraction);
+		void setEnv(float humi, float temp);
 		void reset();
 };
 

src/driver/ccs811.cc

@@ -65,6 +65,11 @@ void CCS811::setEnv(unsigned char humi, unsigned char humi_fraction, unsigned ch
 	i2c.xmit(address, 5, txbuf, 0, rxbuf);
 }
 
+void CCS811::setEnv(float humi, float temp)
+{
+	setEnv(humi * 2, 0, (temp - 25) * 2, 0);
+}
+
 unsigned char CCS811::getStatus()
 {
 	txbuf[0] = 0x00;