configure: Fix check-tcg not executing any tests

After configuring with --target-list=hexagon-linux-user
running `make check-tcg` just prints the following:

```
make: Nothing to be done for 'check-tcg'
```

In the probe_target_compiler function, the 'break'
command is used incorrectly. There are no lexically
enclosing loops associated with that break command which
is an unspecfied behaviour in the POSIX standard.

The dash shell implementation aborts the currently executing
loop, in this case, causing the rest of the logic for the loop
in line 2490 to be skipped, which means no Makefiles are
generated for the tcg target tests.

Fixes: c3b570b5a9 (configure: don't enable
cross compilers unless in target_list)

Signed-off-by: Mukilan Thiyagarajan <quic_mthiyaga@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Link: https://patchew.org/QEMU/20221207082309.9966-1-quic._5Fmthiyaga@quicinc.com/
Message-Id: <20221207082309.9966-1-quic_mthiyaga@quicinc.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20221221090411.1995037-2-alex.bennee@linaro.org>

configure

@@ -1882,9 +1882,7 @@ probe_target_compiler() {
   # We shall skip configuring the target compiler if the user didn't
   # bother enabling an appropriate guest. This avoids building
   # extraneous firmware images and tests.
-  if test "${target_list#*$1}" != "$1"; then
-      break;
-  else
+  if test "${target_list#*$1}" = "$1"; then
       return 1
   fi