init: fix compilation for broken compilers

[lyakh]

Some (broken) compilers fail to handle

struct x {
	union {
		type_a *a;
		type_b *b;
	};
};

correctly. Replace that with an equivalent but simpler

union x {
	type_a *a;
	type_b *b;
};

Sample build failure log: https://sof-ci.01.org/sofpr/PR10113/build13856/build/firmware_community/tgl.log

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[lyakh]

As explained in #93020 this bug can also be reproduced by building pure Zephyr for intel_adsp/cavs25 using the same Cadence toolchain

[henrikbrixandersen]

Some (broken) compilers fail to handle

struct x {
	union {
		type_a *a;
		type_b *b;
	};
};

correctly. Replace that with an equivalent but simpler

union x {
	type_a *a;
	type_b *b;
};

This removes the encapsulation, though. With a struct, more members can be added later without breaking an API.

[cfriedt]

@lyakh - it looks like the code is being compiled with -std=c99. However, anonymous unions were not added to ISO C until C11.

Maybe the compiler isn't actually broken.

Can you try building with the appropriate settings?

With Zephyr, you should be able to use CONFIG_STD_C11=y.