MAINTAINERS: Update for Keystone2 secure devices

Update Keystone2 secure device configs under
"TI SYSTEM SECURITY". Without this buildman keeps complaining
about the status of these boards.
Signed-off-by: NLokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: NTom Rini <trini@konsulko.com>
Acked-by: NAndrew F. Davis <afd@ti.com>

MAINTAINERS

@@ -436,6 +436,9 @@ F:	configs/am335x_hs_evm_defconfig
 F:	configs/am43xx_hs_evm_defconfig
 F:	configs/am57xx_hs_evm_defconfig
 F:	configs/dra7xx_hs_evm_defconfig
+F:	configs/k2hk_hs_evm_defconfig
+F:	configs/k2e_hs_evm_defconfig
+F:	configs/k2g_hs_evm_defconfig
 
 TQ GROUP
 #M:	Martin Krause <martin.krause@tq-systems.de>