defconfigs: Add a config for AM43xx HS EVM with QSPI Boot support

On AM43xx HS devices, QSPI boot is XIP and we use a single stage
bootloader. Add a defconfig for this.

Signed-off-by: Andrew Davis <afd@ti.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index cd54e66..31291d3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1364,6 +1364,7 @@
 F:	configs/am335x_hs_evm_defconfig
 F:	configs/am335x_hs_evm_uart_defconfig
 F:	configs/am43xx_hs_evm_defconfig
+F:	configs/am43xx_hs_evm_qspi_defconfig
 F:	configs/am57xx_hs_evm_defconfig
 F:	configs/am57xx_hs_evm_usb_defconfig
 F:	configs/dra7xx_hs_evm_defconfig