mt76x0: dfs: fix IBI_R11 configuration on non-radar channels

mt76x0: dfs: fix IBI_R11 configuration on non-radar channels

[ Upstream commit 6bf4a8e902aad7df55d7f2b10b850cfa3f880996 ]

Fix IBI_R11 configuration on non-radar channels for mt76x0e
driver. This patch improve system stability under heavy load.
Moreover use IBI_R11 name and remove magic numbers for
0x212c register

Fixes: 0c3b3abc9251 ("mt76x0: pci: add DFS support")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>