Revert "armv7m: Guard against no -kernel argument"

This reverts commit 01fd41a.

The generic loader device (-device loader,file=kernel.bin) can be used
to load a kernel instead of the -kernel option.  Some boards have flash
memory (pflash) that is set via the -pflash or -drive options.

Allow starting QEMU without the -kernel option to accommodate these
scenarios.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190103144124.18917-1-stefanha@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/armv7m.c

@@ -285,11 +285,6 @@ void armv7m_load_kernel(ARMCPU *cpu, const char *kernel_filename, int mem_size)
     big_endian = 0;
 #endif
 
-    if (!kernel_filename && !qtest_enabled()) {
-        error_report("Guest image must be specified (using -kernel)");
-        exit(1);
-    }
-
     if (arm_feature(&cpu->env, ARM_FEATURE_EL3)) {
         asidx = ARMASIdx_S;
     } else {