feat(tc): enable trbe errata flags for Cortex-A520 and X4

Enable following erratas as per the TARGET_PLATFORM of TC
 - ERRATA_A520_2938996
 - ERRATA_X4_2726228

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ia552473740c34867dd9fd619faf378adcb784821
1 file changed