ARM: 8865/1: mm: remove unused variables

ARM: 8865/1: mm: remove unused variables

Fix gcc warnings:

arch/arm/mm/init.c: In function 'mem_init':
arch/arm/mm/init.c:456:13: warning: unused variable 'itcm_end' [-Wunused-variable]
  extern u32 itcm_end;
             ^
arch/arm/mm/init.c:455:13: warning: unused variable 'dtcm_end' [-Wunused-variable]
  extern u32 dtcm_end;
             ^

They are not used any more since
commit 1c31d4e96b8c ("ARM: 8820/1: mm: Stop printing the virtual memory layout")

Link: https://lkml.org/lkml/2019/5/12/82
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>