dt-bindings: pinctrl: qcom,sm8150: Drop duplicate function value "atest_usb2"

The enum value "atest_usb2" appears twice. Remove the duplicate. The
meta-schema normally catches these, but schemas under "$defs" was not
getting checked. A fix for that is pending.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230418150613.1528233-1-robh@kernel.orgSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/qcom,sm8150-pinctrl.yaml

@@ -82,7 +82,7 @@ $defs:
         enum: [ adsp_ext, agera_pll, aoss_cti, ddr_pxi2, atest_char,
                 atest_char0, atest_char1, atest_char2, atest_char3, audio_ref,
                 atest_usb1, atest_usb2, atest_usb10, atest_usb11, atest_usb12,
-                atest_usb13, atest_usb20, atest_usb21, atest_usb22, atest_usb2,
+                atest_usb13, atest_usb20, atest_usb21, atest_usb22,
                 atest_usb23, btfm_slimbus, cam_mclk, cci_async, cci_i2c,
                 cci_timer0, cci_timer1, cci_timer2, cci_timer3, cci_timer4,
                 cri_trng, cri_trng0, cri_trng1, dbg_out, ddr_bist, ddr_pxi0,