ASoC: amd: use int type to store negative error codes

Change the 'ret' variable from u32 to int to store negative error codes
directly or returned by other functions.

Storing the negative error codes in unsigned type, doesn't cause an issue
at runtime but it's ugly as pants. Additionally, assigning negative error
codes to unsigned type may trigger a GCC warning when the -Wsign-conversion
flag is enabled.

No effect on runtime.

Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Message-ID: <20250828075406.386208-2-rongqianfeng@vivo.com>
Signed-off-by: Mark Brown <broonie@kernel.org>