util/docker/coreboot-sdk: Remove libcurl4 from the package list

When installing the packages, apt-get returns an error about holding
broken packages. It occurs the diffutils depends on libcurl4t64
which breaks the libcurl4.

As a solution, remove the libcurl4 from the list, and let the package
manager resolve the dependencies.

TEST=Build coreboot-sdk

Change-Id: Iabc4f74619d4462317d8adb4068e50135d89d80e
Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82066
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

util/docker/coreboot-sdk/Dockerfile

@@ -42,7 +42,6 @@ RUN \
 		less \
 		libcapture-tiny-perl \
 		libcrypto++-dev \
-		libcurl4 \
 		libcurl4-openssl-dev \
 		libdatetime-perl \
 		libelf-dev \