fix(linux): AM62Lx: Add note for jumper position to enter RTC DDR mode

Add a note to ensure correct jumper position to enter RTC Only plus DDR
low power mode.

Signed-off-by: Akashdeep Kaur <a-kaur@ti.com>

Author: akashdeep-ti

source/linux/Foundational_Components/Power_Management/pm_am62lx_low_power_modes.rst

@@ -91,6 +91,11 @@ RTC Only Plus DDR
 RTC Only + DDR mode is the deepest low power mode that allows the system to enter a state of lowest power consumption
 while still retaining the DDR RAM context.
 
+.. important::
+
+   Jumper J14 position on the EVM determines which low power mode is entered. For RTC Only + DDR mode,
+   connect jumper J14 to the position marked as "RTC + DDR MODE" (different from RTC Only Mode).
+
 In order to enter RTC Only + DDR mode, first disable USB0 and USB1 as wakeup
 sources.