BANK_SELECT should always be FRAGMENT_SIZE + 3 due to 8-entry (2^3)
per cache line in L2 TLB for Vega10.

v2: agd: fix warning
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Roger He <Hongbo.He@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>