treewide: Migrate CONFIG_SYS_ALT_MEMTEST to Kconfig

Migrate the CONFIG_SYS_ALT_MEMTEST option to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
[trini: Re-run migration after also including CMD_MEMTEST]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/xilinx_zynqmp_zc1751_xm019_dc5_defconfig b/configs/xilinx_zynqmp_zc1751_xm019_dc5_defconfig
index 47edf51..45b2e69 100644
--- a/configs/xilinx_zynqmp_zc1751_xm019_dc5_defconfig
+++ b/configs/xilinx_zynqmp_zc1751_xm019_dc5_defconfig
@@ -18,6 +18,7 @@
 CONFIG_SPL_RAM_DEVICE=y
 CONFIG_SYS_PROMPT="ZynqMP> "
 CONFIG_CMD_MEMTEST=y
+CONFIG_SYS_ALT_MEMTEST=y
 CONFIG_CMD_CLK=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_FPGA_LOADBP=y