Such improvement is possible due to reduction of the need to invalidate
redundant data, which resides in L2 cache.
Since the sent USB request size at once is 512B (L1 - 32 KiB in total) -
one can be quite confident that it is already available in L1 and L2 can
be disabled.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> Acked-by: Minkyu Kang <mk7.kang@samsung.com>