samples: wifi: radio_test: Improve tone trasmit command description

[SHEL-3378] Correct description for tx tone transmission subcommand.

Signed-off-by: Prasun Sinha <[email protected]>

Author: prsi98

samples/wifi/radio_test/radio_test_subcommands.rst

@@ -170,7 +170,8 @@ Wi-Fi radio test subcommands
      - | <val> (Min: -10, Max: 10)
      - 0
      - Configuration
-     - Transmit tone frequency in the range of -10 MHz to 10 MHz.
+     - Tone frequency in the range of -10 MHz to 10 MHz with a resolution of 1 MHz.
+       The transmit tone frequency will be offset from the center frequency of the selected channel.
    * - dpd
      - | 0 - DPD bypass
        | 1 - Enable DPD

samples/wifi/radio_test/src/nrf_wifi_radio_test_shell.c

@@ -2400,7 +2400,7 @@ SHELL_STATIC_SUBCMD_SET_CREATE(
 		      0),
 	SHELL_CMD_ARG(tx_tone_freq,
 		      NULL,
-		      "<val> - Frequency in the range of -10MHz to 10MHz",
+		      "<val> - Frequency offset with respect to center frequency in the range of -10MHz to 10MHz (resolution 1MHz)",
 		      nrf_wifi_radio_test_set_tx_tone_freq,
 		      2,
 		      0),