brcmfmac: increase dcmd maximum buffer size

Increase dcmd maximum buffer size to match firmware
configuration for new chips.

Signed-off-by: Lo(Double)Hsiang Lo <double.lo@cypress.com>
Signed-off-by: Chi-Hsien Lin <chi-hsien.lin@cypress.com>
Signed-off-by: Ian Lin <ian.lin@infineon.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220922104140.11889-4-ian.lin@infineon.com