Cross Compile - Configure command is not working

[AnnalakshmiSuriyanarayanan]

Host: Ubuntu/Debian x86_64
Target: RK3288 (ARM) 32 bit
Toolchain: Linaro GCC 7.5.0
Qt version: 5.15.2

Folder structure:
~/rk3288Sources/
├── gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf/
├── DebianSysroot/
├── qt-everywhere-src-5.15.2/
└── build-rk3288/

And my qmake.conf is

MAKEFILE_GENERATOR = UNIX
CONFIG += incremental
QMAKE_INCREMENTAL_STYLE = sublib

include(../../common/linux.conf)
include(../../common/gcc-base-unix.conf)
include(../../common/g++-unix.conf)

QMAKE_CC = arm-linux-gnueabihf-gcc
QMAKE_CXX = arm-linux-gnueabihf-g++
QMAKE_LINK = arm-linux-gnueabihf-g++
QMAKE_LINK_SHLIB = arm-linux-gnueabihf-g++

QMAKE_AR = arm-linux-gnueabihf-ar cqs
QMAKE_OBJCOPY = arm-linux-gnueabihf-objcopy
QMAKE_STRIP = arm-linux-gnueabihf-strip

load(qt_config)

Build command (run from build-rk3288):
../qt-everywhere-src-5.15.2/configure
-release -opengl es2
-device linux-rk3288-g++
-device-option CROSS_COMPILE=...
-sysroot ~/rk3288Sources/DebianSysroot
-prefix /usr/local/qt5
-nomake tests -nomake examples

when i ran the above build command and got this error
Project ERROR: You cannot configure qt separately within a top-level build.

can you help me for find solution?
Thanks in advance