soc: espressif: esp32s3: Adjust BOOTLOADER_DRAM_SEG_LEN for worst case

Larger image partitions require more space in DRAM due to
the increase in .bss.sector_buffers.
Each sector in .bss.sector_buffers consumes 16 bytes.
In the worst case scenario, such as with the ESP32S3 N32R8V,
which has 32 MB of flash and most likely 12 MB image partition,
an addition of 0xc000 should be sufficient to accommodate this.

Signed-off-by: Nik Schewtschuk <nikita.schewtschuk@smartmechatronics.de>