brcmfmac: Use firmware_request_nowarn for the clm_blob

[ Upstream commit 4ad0be160544ffbdafb7cec39bb8e6dd0a97317a ]

The linux-firmware brcmfmac firmware files contain an embedded table with
per country allowed channels and strength info.

For recent hardware these versions of the firmware are specially build for
linux-firmware, the firmware files directly available from Cypress rely on
a separate clm_blob file for this info.

For some unknown reason Cypress refuses to provide the standard firmware
files + clm_blob files it uses elsewhere for inclusion into linux-firmware,
instead relying on these special builds with the clm_blob info embedded.
This means that the linux-firmware firmware versions often lag behind,
but I digress.

The brcmfmac driver does support the separate clm_blob file and always
tries to load this. Currently we use request_firmware for this. This means
that on any standard install, using the standard combo of linux-kernel +
linux-firmware, we will get a warning:
"Direct firmware load for ... failed with error -2"

On top of this, brcmfmac itself prints: "no clm_blob available (err=-2),
device may have limited channels available".

This commit switches to firmware_request_nowarn, fixing almost any brcmfmac
device logging the warning (it leaves the brcmfmac info message in place).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>