[server-21.1-branch] build: Drop libxcvt requirement from SDK_REQUIRED_MODULES
The SDK doed not need libxcvt, only Xorg and Xwayland do.
Closes: #1721 (closed)
Fixes: a4ab57cb - build: Add dependency on libxcvt
Signed-off-by: Olivier Fourdan ofourdan@redhat.com