refactor(ethos-n): move build flags to ethosn_npu.mk

The build flags to enable the Arm(R) Ethos(TM)-N NPU driver are in arm
platform specific make files i.e. plat/arm/common/arm_common.mk. These
flags are renamed and moved to ethosn_npu.mk. Other source and make
files are changed to reflect the changes in these flags.

Signed-off-by: Rajasekaran Kalidoss <rajasekaran.kalidoss@arm.com>
Change-Id: I6fd20225343c574cb5ac1f0f32ff2fc28ef37ea6
17 files changed