Do not remove the -m option for loongarch64

(From OE-Core rev: 6f3583675d31b74a3ae1c7fae450ea1624acc2e7)

Signed-off-by: Jialing Zhang <zhangjialing@loongson.cn>
Signed-off-by: Qizheng Zhu <zhuqizheng@loongson.cn>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/runqemu

@@ -811,7 +811,7 @@ to your build configuration.
         self.set('QB_MEM', qb_mem)
 
         mach = self.get('MACHINE')
-        if not mach.startswith(('qemumips', 'qemux86')):
+        if not mach.startswith(('qemumips', 'qemux86', 'qemuloongarch64')):
             self.kernel_cmdline_script += ' mem=%s' % self.get('QB_MEM').replace('-m','').strip() + 'M'
 
         self.qemu_opt_script += ' %s' % self.get('QB_MEM')