.travis.yml: drop 32 bit systems from MAIN_SOFTMMU_TARGETS

The older clangs are still struggling to build and run everything
withing the 50 minute timeout so lets lighten the load a bit more. We
still have coverage for GCC and hopefully no obscure 32 bit guest only
breakages slip through the cracks.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
diff --git a/.travis.yml b/.travis.yml
index b9a026c..c09b6a0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -79,7 +79,7 @@
     - BASE_CONFIG="--disable-docs --disable-tools"
     - TEST_CMD="make check V=1"
     # This is broadly a list of "mainline" softmmu targets which have support across the major distros
-    - MAIN_SOFTMMU_TARGETS="aarch64-softmmu,arm-softmmu,i386-softmmu,mips-softmmu,mips64-softmmu,ppc64-softmmu,riscv64-softmmu,s390x-softmmu,x86_64-softmmu"
+    - MAIN_SOFTMMU_TARGETS="aarch64-softmmu,mips64-softmmu,ppc64-softmmu,riscv64-softmmu,s390x-softmmu,x86_64-softmmu"
     - CCACHE_SLOPPINESS="include_file_ctime,include_file_mtime"
     - CCACHE_MAXSIZE=1G