wifi: ath12k: cleanup ath12k_mac_mlo_ready()

There is a possibility for an uninitialized *ret* variable to be
returned in some code paths.

This explicitly returns 0 without an error. Also removes goto that
returned *ret* and simply returns in place.

Closes: https://scan5.scan.coverity.com/#/project-view/63541/10063?selectedIssue=1642337


Fixes: b716a10d ("wifi: ath12k: enable MLO setup and teardown from core")
Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
Reviewed-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Link: https://patch.msgid.link/20250210-ath12k-uninit-v2-1-3596f28dd380@ethancedwards.com


Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>