tests: Remove firmware bits from unrelated tests

The pci-bridge-many-disks test case is not related to firmware
handling at all, so we can trim it without losing any coverage.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

tests/qemuxml2argvdata/pci-bridge-many-disks.args

@@ -14,7 +14,6 @@ QEMU_AUDIO_DRV=none \
 -machine pc,usb=off,dump-guest-core=off \
 -accel tcg \
 -cpu qemu64,kvmclock=off \
--bios /usr/share/seabios/bios.bin \
 -m 3907 \
 -overcommit mem-lock=off \
 -smp 1,sockets=1,cores=1,threads=1 \

tests/qemuxml2argvdata/pci-bridge-many-disks.xml

@@ -5,7 +5,6 @@
   <currentMemory unit='KiB'>4000000</currentMemory>
   <os>
     <type arch='x86_64' machine='pc'>hvm</type>
-    <loader>/usr/share/seabios/bios.bin</loader>
     <boot dev='hd'/>
   </os>
   <features>

tests/qemuxml2xmloutdata/pci-bridge-many-disks.xml

@@ -6,7 +6,6 @@
   <vcpu placement='static'>1</vcpu>
   <os>
     <type arch='x86_64' machine='pc'>hvm</type>
-    <loader type='rom'>/usr/share/seabios/bios.bin</loader>
     <boot dev='hd'/>
   </os>
   <features>