Add --without-debuginfod flag to binutils and gdb config

Add additional build flag to prevent build errors due to a missing
libdebuginfo dependency when building on ubuntu 20.04 for mingw builds.
This build dependency was a result of switching the cross toolchain
builds from centos7 to rhe8.
More info see https://jira.arm.com/browse/GNUTOOLS-15268

The static linking patch of gcc2 stage has also been reverted due to build failures on rhe8.
Moving the mingw builds back to ubuntu has made that patch redundant.

Change-Id: I6e03d1c9abf5daf7a7f1f23e55539ce39eeafcbd