[BUG] Documentation - build system misalignment

[kr-t]

Is it a security vulnerability?
No

Describe the bug
Documentation states, that when WASM Interpreter is on, the fast one shall be the default one:
https://github.com/bytecodealliance/wasm-micro-runtime/blob/main/doc/build_wamr.md#configure-interpreters

Nevertheless, while it's true for the Linux/Posix platforms (here:

wasm-micro-runtime/product-mini/platforms/linux/CMakeLists.txt

Line 84 in 10c36f4

set (WAMR_BUILD_FAST_INTERP 1)

and here:

wasm-micro-runtime/CMakeLists.txt

Line 84 in 10c36f4

set (WAMR_BUILD_FAST_INTERP 1)

It isn't true, when build for Zephyr (and maybe other platforms): since WAMR_BUILD_FAST_INTERP is neither explicitly set here for example:
https://github.com/bytecodealliance/wasm-micro-runtime/blob/main/product-mini/platforms/zephyr/simple/CMakeLists.txt
nor here:
https://github.com/bytecodealliance/wasm-micro-runtime/blob/main/build-scripts/runtime_lib.cmake

It seems to default to classic interpreter, probably here, but I'm not sure:

wasm-micro-runtime/core/iwasm/interpreter/iwasm_interp.cmake

Line 13 in 10c36f4

set (INTERPRETER "wasm_interp_classic.c")

Version
main: 10c36f4

To Reproduce
Steps to reproduce the behavior:

1. Compile iwasm for Linux, get following:

cmake ..
-- WAMR version: 2.4.3
-- Build Configurations:
     Build as target X86_64
     Build for platform linux
     ...
     WAMR Interpreter enabled
     Fast interpreter enabled

2. Compile for Zephyr, get following (from: https://github.com/bytecodealliance/wasm-micro-runtime/blob/main/product-mini/platforms/zephyr/simple/README.md)

west build . -b qemu_cortex_a53 -p always -- -DWAMR_BUILD_TARGET=AARCH64 
...
-- WAMR version: 2.4.3
-- Build Configurations:
     Build as target AARCH64
     Build for platform zephyr
     ...
     WAMR Interpreter enabled
     Fast interpreter disabled

Desktop (please complete the following information):

• Arch: x86_64
• Board: native x86 and qemu_cortex_a53
• OS: Ubuntu WSL
• Version 24

Additional context
If this isn't intended I would gladly submit a PR fixing this, just wanted to have a confirmation before starting.