tcl/target/ti_k3: Add AM243 SoC

Add support for the TI K3 family AM243 SoC. This SoC is built on the
same base of AM642, so reuse the configuration with the exception of
Cortex-A53 which is not available on this device.

For further details, see https://www.ti.com/lit/pdf/spruim2

Change-Id: I971ba878b0f503e5120f6853634776eb61d05080
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7946
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

tcl/target/ti_k3.cfg

@@ -2,6 +2,8 @@
 # Copyright (C) 2019-2021 Texas Instruments Incorporated - http://www.ti.com/
 #
 # Texas Instruments K3 devices:
+# * AM243: https://www.ti.com/lit/pdf/spruim2
+#  Has 4 R5 Cores, M4F and an M3
 # * AM625: https://www.ti.com/lit/pdf/spruiv7a
 #  Has 4 ARMV8 Cores and 1 R5 Core and an M4F
 # * AM62A7: https://www.ti.com/lit/pdf/spruj16a
@@ -85,6 +87,7 @@ switch $_soc {
 		# Sysctrl power-ap unlock offsets
 		set _sysctrl_ap_unlock_offsets {0xf0 0x50}
 	}
+	am243 -
 	am642 {
 		set _K3_DAP_TAPID 0x0bb3802f
 
@@ -102,6 +105,12 @@ switch $_soc {
 
 		# M4 processor
 		set _gp_mcu_cores 1
+
+		# Overrides for am243
+		if { "$_soc" == "am243" } {
+			# Uses the same JTAG ID
+			set _armv8_cores 0
+		}
 	}
 	am625 {
 		set _K3_DAP_TAPID 0x0bb7e02f