wireless-regdb: Raise DFS TX power limit to 250 mW (24 dBm) for the US

According to 47 CFR § 15.407(a)(2), the U-NII-2A (5.25-5.35 GHz) and
U-NII-2C (5.47-5.725 GHz) DFS bands are subject to the following [1]:
"For the 5.25-5.35 GHz and 5.47-5.725 GHz bands, the maximum conducted
 output power over the frequency bands of operation shall not exceed
 the lesser of 250 mW or 11 dBm + 10 log B, where B is the 26 dB
 emission bandwidth in megahertz."

As such, increase the TX power limit for the U-NII-2A and U-NII-2C DFS
bands to 250 mW (24 dBm) to match the FCC's current rules. These power
limits have remained unchanged since the § 15.407 amendment by the FCC
in 2014 [2].

[1] https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-E/section-15.407#p-15.407(a)(2)
[2] https://www.federalregister.gov/d/2014-09279/p-131

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Seth Forshee <sforshee@kernel.org>
diff --git a/db.txt b/db.txt
index 6e8dbef..b898799 100644
--- a/db.txt
+++ b/db.txt
@@ -1596,12 +1596,12 @@
 	(2400 - 2472 @ 40), (30)
 	# 5.15 ~ 5.25 GHz: 30 dBm for master mode, 23 dBm for clients
 	(5150 - 5250 @ 80), (23), AUTO-BW
-	(5250 - 5350 @ 80), (23), DFS, AUTO-BW
+	(5250 - 5350 @ 80), (24), DFS, AUTO-BW
 	# This range ends at 5725 MHz, but channel 144 extends to 5730 MHz.
 	# Since 5725 ~ 5730 MHz belongs to the next range which has looser
 	# requirements, we can extend the range by 5 MHz to make the kernel
 	# happy and be able to use channel 144.
-	(5470 - 5730 @ 160), (23), DFS
+	(5470 - 5730 @ 160), (24), DFS
 	(5730 - 5850 @ 80), (30), AUTO-BW
 	# https://www.federalregister.gov/documents/2021/05/03/2021-08802/use-of-the-5850-5925-ghz-band
 	# max. 33 dBm AP @ 20MHz, 36 dBm AP @ 40Mhz+, 6 dB less for clients