platformmeson: fix AFBC 32x8 feature support
Since MALI_GRALLOC_INTFMT_AFBC_BASIC is mandatory even to enable 32x8 block size, do not OR 32x8 and 16x16 overwise the final modifier will be invalid.
Since MALI_GRALLOC_INTFMT_AFBC_BASIC is mandatory even to enable 32x8 block size, do not OR 32x8 and 16x16 overwise the final modifier will be invalid.