Chinese businesses have been employing their own kind for years on end. If this is not discrimination, then, what is? Using the reason of Mandarin or Chinese dialects as having an advantage in business is no longer a valid reason in this day and age because even Chinese in CHina is fast taking up English.
If Maybank wishes to implement their policy of favouring a company that has at least 50% bumiputera stake (Bumiputera population in Malaysia is roughly 65%), it can do so, but do not declare it openly.
No reputable Chinese owned companies will make it an open policy to favour Chinese but of course the tacit understanding is such. So, do the same if Maybank wishes to do so.
I am sure it is not as difficult to find a lawyer's firm that fit the requirement as well as being an efficient law firm to boot.