[Arista] Update config.bcm of 7060_cx32s for handling 40g optics with unreliable los settings (#17768)

For 40G optics there is SAI handling of T0 facing ports to be set with SR4 type and unreliable los set for a fixed set of ports. For this property to be invoked the requirement is set
phy_unlos_msft=1 in config.bcm.
This change is to meet the requirement and once this property is set, the los/interface type settings is applied by SAI on the required ports.

Why I did it
For Arista-7060CX-32S-Q32 T1, 40G ports RX_ERR minimalization during connected device reboot
can be achieved by turning on Unreliable LOS and SR4 media_type for all ports which are connected to T0.

The property phy_unlos_msft=1 is to exclusively enable this property.

Microsoft ADO: 25941176

How I did it
Changes in SAI and turning on property

How to verify it
Ran the changes on a testbed and verified configurations are as intended.

with property

admin@sonic2:~$ bcmcmd "phy diag xe8 dsc config" | grep -C 2 "LOS"
Brdfe_on                    = 0
Media Type                  = 2
Unreliable LOS              = 1
Scrambling Disable          = 0
Lane Config from PCS        = 0

without property

admin@sonic:~$ bcmcmd "phy diag xe8 dsc config" | grep -C 2 "LOS"
Brdfe_on                    = 0
Media Type                  = 0
Unreliable LOS              = 0
Scrambling Disable          = 0
Lane Config from PCS        = 0

Signed-off-by: vaibhav-dahiya <[email protected]>

Author: vdahiya12

device/arista/x86_64-arista_7060_cx32s/Arista-7060CX-32S-Q32/th-a7060-cx32s-32x40G-t1.config.bcm

@@ -449,3 +449,4 @@ serdes_preemphasis_109=0x145c00
 
 mmu_init_config="MSFT-TH-Tier1"
 phy_an_lt_msft=1
+phy_unlos_msft=1

src/sonic-device-data/tests/permitted_list

@@ -326,6 +326,7 @@ phy_pcs_repeater
 l3_alpm_hit_skip
 sai_verify_incoming_chksum
 phy_an_lt_msft
+phy_unlos_msft
 system_ref_core_clock_khz
 xflow_macsec_secure_chan_to_num_secure_assoc_encrypt
 xflow_macsec_secure_chan_to_num_secure_assoc_decrypt