iio: chemical: scd30: make command lookup table const

scd30_i2c_cmd_lookup_tbl contains fixed opcodes and is
only read by scd30_i2c_command(). Make it const to document that it's immutable
and allow it to be placed in read-only memory.

Signed-off-by: Giorgi Tchankvetadze <giorgitchankvetadze1997@gmail.com>
Reviewed-by: Stepan Ionichev <sozdayvek@gmail.com>
Acked-by: Maxwell Doose <m32285159@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: Giorgi Tchankvetadze

drivers/iio/chemical/scd30_i2c.c

@@ -20,7 +20,7 @@
 #define SCD30_I2C_MAX_BUF_SIZE 18
 #define SCD30_I2C_CRC8_POLYNOMIAL 0x31
 
-static u16 scd30_i2c_cmd_lookup_tbl[] = {
+static const u16 scd30_i2c_cmd_lookup_tbl[] = {
 	[CMD_START_MEAS] = 0x0010,
 	[CMD_STOP_MEAS] = 0x0104,
 	[CMD_MEAS_INTERVAL] = 0x4600,