Refactor Hexagon backend support checks

[max-krasnyansky]

This change refactors ggml/src/ggml-hexagon/ggml-hexagon.cpp by removing several static helper functions used for checking tensor types and dimensions. The logic from these functions (hex_supported_src0_type, hex_supported_src1_type, etc.) has been inlined directly into the functions that use them (e.g., ggml_hexagon_supported_binary, ggml_hexagon_supported_add_id). This makes it easier to see at a glance which types are supported for a given Hexagon backend operation. Additionally, the unused hex_supported_dims function was removed. The codebase was successfully compiled to ensure no regressions.

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PR created automatically by Jules for task 13200797414275192595 started by @max-krasnyansky

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