camera(Camera_NHX): add NHX validation + CAMX helpers + LAVA integration

[smuppand]

This PR adds an end-to-end Camera_NHX validation flow for CAMX/NHX-based camera stacks, and wires it into LAVA in the standard qcom-linux-testkit style.

What’s included

• functestlib.sh
  • Improved check_dependencies handling (supports passing a single space-separated string)
  • Strengthened scan_dmesg_errors behavior (better filtering/output for camera logs)
• Runner/utils/camera/lib_camera.sh
  • New CAMX/NHX helper functions (DT/opkg/firmware checks, fdtdump camera node detection)
  • NHX dump discovery + checksum validation helper (writes dump list + checksums)
• Runner/suites/Multimedia/Camera/Camera_NHX/run.sh
  • Uses shared helpers from functestlib.sh and lib_camera.sh
  • Collects NHX logs, validates dumps (non-empty + checksum), creates summary + .res
• LAVA
  • Adds Camera_NHX_Preview.yaml test definition invoking the suite runner and exporting results via send-to-lava.sh
• Docs
  • Adds README.md for Camera_NHX with usage, prerequisites, logs/output layout, and LAVA usage

Notes

Sensor enumeration is warn-only (NHX may still run), but CAMX graph bind and required firmware are gated.
Dump validation ensures files exist and are non-zero; checksums are generated for traceability.

[abbajaj806]

while read loops have inverted logic
This skips non-empty lines and processes only empty ones (opposite of what you want).

[smuppand]

while read loops have inverted logic This skips non-empty lines and processes only empty ones (opposite of what you want).

if line is empty → -n is false → false || continue → continue → empty lines skipped
if line is non-empty → -n is true → true || continue → does not continue → line processed
So it does not “skip non-empty lines and process only empty ones”.

[abbajaj806]

LGTM