Problems with BIF Attribute [bootimage]

The [bootimage] attribute seems to modify the state of the original partition in the input image, especially the partition with the [offset] attribute specified.

The test process is as follows：

I used the following bif file to generate an image called BASE_BOOT.BIN
```
the_loader_image:  
{                                         
[bootloader] ./images/linux/zynq_fsbl.elf
./images/linux/system.bit
./images/linux/u-boot.elf
[load=0x00100000] ./images/linux/system.dtb
[offset=0x440000, partition_owner=uboot] ./images/linux/boot.scr
} 
```
2.Then I used the following bif file to generate another image called RE_BASE_BOOT.BIN
```
the_ROM_image:
{
[bootimage] ./images/linux/BASE_BOOT.BIN
}
```
3.BASE_BOOT.BIN and RE_BASE_BOOT.BIN are not the same size, so I compared the binary content of the two files. I found that the address of the ./images/linux/boot.scr partition has changed， Its starting address becomes the address immediately following the ./images/linux/system.dtb partition，In other words, the [offset] attribute of the ./images/linux/boot.scr partition is invalid

I don’t know if this is a bug, and I want to know how to avoid this problem: do not modify the original state of the input partition when using the [bootimage] attribute

Xilinx / bootgen

Problems with BIF Attribute [bootimage] #18