Add section sketch_boot for nano 33 IoT

Author: giulcioffi

variants/nano_33_iot/linker_scripts/gcc/flash_with_bootloader.ld

@@ -67,6 +67,9 @@ SECTIONS
 	{
 		__text_start__ = .;
 
+		KEEP(*(.sketch_boot))
+		. = ALIGN(0x2000);
+
 		KEEP(*(.isr_vector))
 		*(.text*)