zephyr: boards: enable progressive erase for RT1050 and RT1060

RT1050 and 1060 have large flash chips, so tools like MCUMgr will time
out if the entire flash bank is erased before writing data. Enable
progressive erase for these boards to prevent timeouts.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
diff --git a/boot/zephyr/boards/mimxrt1050_evk_qspi.conf b/boot/zephyr/boards/mimxrt1050_evk_qspi.conf
index 37ed5f8..7850953 100644
--- a/boot/zephyr/boards/mimxrt1050_evk_qspi.conf
+++ b/boot/zephyr/boards/mimxrt1050_evk_qspi.conf
@@ -1,4 +1,5 @@
-# Copyright 2021 NXP
+# Copyright 2021-2022 NXP
 # SPDX-License-Identifier: Apache-2.0
 
 CONFIG_BOOT_MAX_IMG_SECTORS=1024
+CONFIG_BOOT_ERASE_PROGRESSIVELY=y
diff --git a/boot/zephyr/boards/mimxrt1060_evk.conf b/boot/zephyr/boards/mimxrt1060_evk.conf
index 37ed5f8..7850953 100644
--- a/boot/zephyr/boards/mimxrt1060_evk.conf
+++ b/boot/zephyr/boards/mimxrt1060_evk.conf
@@ -1,4 +1,5 @@
-# Copyright 2021 NXP
+# Copyright 2021-2022 NXP
 # SPDX-License-Identifier: Apache-2.0
 
 CONFIG_BOOT_MAX_IMG_SECTORS=1024
+CONFIG_BOOT_ERASE_PROGRESSIVELY=y