GPU-DRM-GMA500: Use kmalloc_array() in mid_get_vbt_data_r10()

[SF Markus Elfring]

>> A multiplication for the size determination of a memory allocation
>> indicated that an array data structure should be processed.
>> Thus use the corresponding function "kmalloc_array".
>>
>> This issue was detected by using the Coccinelle software.
> 
> Did you test this running on the hardware?

No. - My "test computer" does not provide the corresponding hardware for the
affected driver source files.

Regards,
Markus