Revert "Makefile: Only set host toolchain if exists"
Revert "Makefile: Only set host toolchain if exists"

This reverts commit 9935980b106f49cf524b07e83c6333cde3294cd3.

Reason for revert: Found a less intrusive option.

Original change's description:
> Makefile: Only set host toolchain if exists
>
> To fix building outside of the chroot, only set the
> CROSS_COMPILE_HOST_DEFAULT to x86_64-pc-linux-gnu- if the compiler
> actually exists.
>
> BRANCH=None
> BUG=b:246424843
> TEST=make test-coverage # in chroot
> TEST=make test-coverage # in gitlab docker
> TEST=emerge-corsola chromeos-ec
>
> Force-Relevant-Builds: all
> Signed-off-by: Jeremy Bettis <jbettis@google.com>
> Change-Id: Icc134eb987033012188a7c77860d8115c41b4df4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3902029
> Tested-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
> Commit-Queue: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
> Auto-Submit: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
> Reviewed-by: Yuval Peress <peress@google.com>
> Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
> Code-Coverage: Aaron Massey <79529a820df71f45023239a3663736629646cc34@google.com>

Bug: b:246424843
CQ-Depend: chromium:3905359
Change-Id: I629f72e949165dbd62f8c5beca73ce0e6c317d10
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3905358
Tested-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-by: Tom Hughes <fc5c12f30a5ed2baa0581f44ee14ad1eb7b20d83@chromium.org>
Reviewed-by: Aaron Massey <79529a820df71f45023239a3663736629646cc34@google.com>
Commit-Queue: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec