EmbeddedPkg/EmbeddedPkg.dsc: fix build for non-ARM architectures

EmbeddedPkg/EmbeddedPkg.dsc: fix build for non-ARM architectures

EmbeddedPkg should be architecture agnostic, but a few issues were
preventing other architectures to build individual components directly
from the .dsc:

- The AndroidBoot/AndroidFastBoot support have a dependency on BdsLib,
  which only has resolutions for ARM/AARCH64. Move them to an
  arch-restricted Components section.
- The Isp1761UsbDxe driver is not 64-bit compatible. It should be
  converted to UEFI driver model, but for now just move it to a new
  Components.ARM section. (Also delete non-useful declaration for
  AARCH64 in EmbeddedPkg.dec.)
- Lan9118Dxe has an unused ArmLib entry. Drop it.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>