New Toolchain support by GCC_ARM for LPC824

Hello All
New adding two file.
LPC824.ld, startup_LPC824.s
Small modification two file.
system_LPC8xx.c, targets.py

Modification reason.

system_LPC8xx.c, result compile.

system_LPC8xx.c:341:21: warning: unused variable 'i' [-Wunused-variable]
[DEBUG] Output:    volatile uint32_t i;

This warning is solved by this code.

Please confirm that.
If you have any question please let me know.

Best regards,
Thank you, I forget delete line 341.
Complete to Delete.