brcmfmac: set F2 blocksize for 4373

Set F2 blocksize to 256 bytes for 4373. It fixes DMA error while having
UDP bi-directional traffic. Also use a defined F1 MesBusyCtrl value.

Signed-off-by: Wright Feng <wright.feng@cypress.com>
Signed-off-by: Chi-hsien Lin <chi-hsien.lin@cypress.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200529034938.124533-2-chi-hsien.lin@cypress.com