dt-bindings: arm: qcom: Document Shikra and its EVK boards

Shikra is a Qualcomm IoT SoC available in a System-on-Module (SoM)
form factor. The SoM integrates the Shikra SoC, PMICs, and essential
passives, and is designed to be mounted on carrier boards.

Three eSoM variant are introduced:
  - CQM: retail variant with integrated modem (PM4125 and PM8005 PMIC)
  - CQS: retail variant without modem (PM4125 and PM8005 PMIC)
  - IQS: industrial-grade variant without modem (PM8150 PMIC)

Each SoM variant pairs with a common EVK carrier board provides debug
UART, USB, and other peripheral interfaces.

Add compatible strings for the CQ2390M, CQ2390S, IQ2390S SoM variant and
its corresponding EVK boards.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Komal Bajaj <komal.bajaj@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260612-shikra-dt-v6-1-6b6cb58db477@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Documentation/devicetree/bindings/arm/qcom.yaml

@@ -971,6 +971,24 @@ properties:
               - xiaomi,polaris
           - const: qcom,sdm845
 
+      - items:
+          - enum:
+              - qcom,shikra-cqm-evk
+          - const: qcom,shikra-cqm-som
+          - const: qcom,shikra
+
+      - items:
+          - enum:
+              - qcom,shikra-cqs-evk
+          - const: qcom,shikra-cqs-som
+          - const: qcom,shikra
+
+      - items:
+          - enum:
+              - qcom,shikra-iqs-evk
+          - const: qcom,shikra-iqs-som
+          - const: qcom,shikra
+
       - items:
           - enum:
               - qcom,sdx55-mtp