fix(linux): Update the PCIe cable model name and the supplier

The hardware setup details in PCIe Endpoint documentation points to an
incorrect link for an equivalent PCIe male to male connector cable.

Update the model name as well as the link, which points to the correct
supplier to obtain the correct cables.

Signed-off-by: Aksh Garg <a-garg7@ti.com>

Author: AkshGarg-19

source/linux/Foundational_Components/Kernel/Kernel_Drivers/PCIe/PCIe_End_Point.rst

@@ -116,7 +116,13 @@ PCIe End Point
 
 .. Image:: /images/Pcie_ep_cable.jpg
 
-An equivalent cable can be obtained from DigiKey (https://www.digikey.com/en/products/detail/3m/8kj2-0743-0250/5128345).
+Obtain the above cable with model name PE-FLEX1-G2-MMCX-12-TI1 from
+https://www.adexelec.com/pe-flex1-4-8-16. Please reach out to them for
+further details.
+
+.. ifconfig:: CONFIG_part_family in ('J7_family')
+
+   For x4-lane applications, use the cable with model PE-FLEX4-G2-MMCX-12-TI1.
 
 Modify the cable to remove resistors in CK+ and CK- in order to avoid
 ground loops (power) and smoking clock drivers (clk+/-).