feat(linux): update 12.00.00 release notes for power improvements

In SDK 12.0, MCU Only power consumption decreased significantly.
Highlight this in the release notes.

Signed-off-by: Kendall Willis <k-willis@ti.com>

Author: kwillis01

source/devices/AM62PX/linux/Release_Specific_Release_Notes.rst

@@ -53,6 +53,7 @@ What's new
   - Review Issue Tracker Section for the new fixes.
   - Security: ATF and OPTEE memory firewall for isolation from Linux
   - Security: Yocto reference for LUKS2 root filesystem encryption with fTPM key management
+  - Power: Reduced power consumption using MCU Only low power mode by 35%
 
 **Key Release References:**
 

source/devices/AM62X/linux/Release_Specific_Release_Notes.rst

@@ -50,6 +50,7 @@ What's new
   - Review Issue Tracker Section for the new fixes.
   - Security: ATF and OPTEE memory firewall for isolation from Linux
   - Security: Yocto reference for LUKS2 root filesystem encryption with fTPM key management
+  - Power: Reduced power consumption using MCU Only low power mode by 13%
 
 **Key Release References:**