Add frequencies for Philippines

There are three different frequencies available for Meshtastic
in the Philippines, each with pros and cons:
433 - 434.7 MHz <10 mW erp
868 - 869.4 MHz <25 mW erp
915 - 918 MHz <250 mW EIRP, no external antennna allowed

Philippines may also use LORA_24 unrestricted at up to 10mW, or up to
250mW if there is no external antennna.

Frequency rules in the Philippines are determined by aggregating the
information in laws, following the circulars referenced in the
[National Radio Frequency Allocation Table (NRFAT)](https://ntc.gov.ph/wp-content/uploads/2022/frequencyallocations/NRFAT_Rev_2020.pdf)
and then circulars that amend the circulars referenced in the NRFAT.
A full description of the regulatory basis can be found in the github issue:
#4948 (comment)

For 433MHz and 868MHz we refer to the Low Power Equipment rules for
"Non-specific Short Range Devices, Telemetry, Telecommand, Alarms,
Data In General and Other Similar Applications.".

For 915MHz and Wireless Data Network Services indoor device rules.

A device approved by the NTC is required for any use of Meshtastic
in the Philippines.

fixes #4948

src/mesh/RadioInterface.cpp

@@ -136,6 +136,17 @@ const RegionInfo regions[] = {
     */
     RDEF(SG_923, 917.0f, 925.0f, 100, 0, 20, true, false, false),
 
+    /*
+        Philippines
+                433 - 434.7 MHz <10 mW erp, NTC approved device required
+                868 - 869.4 MHz <25 mW erp, NTC approved device required
+                915 - 918 MHz <250 mW EIRP, no external antennna allowed
+                https://github.com/meshtastic/firmware/issues/4948#issuecomment-2394926135
+    */
+
+    RDEF(PH_433, 433.0f, 434.7f, 100, 0, 10, true, false, false), RDEF(PH_868, 868.0f, 869.4f, 100, 0, 14, true, false, false),
+    RDEF(PH_915, 915.0f, 918.0f, 100, 0, 24, true, false, false),
+
     /*
        2.4 GHZ WLAN Band equivalent. Only for SX128x chips.
     */
@@ -614,4 +625,4 @@ size_t RadioInterface::beginSending(meshtastic_MeshPacket *p)
 
     sendingPacket = p;
     return p->encrypted.size + sizeof(PacketHeader);
-}
+}