lava: Extend timeouts due to Minnowboard memory cleaning issue

Minnowboard currently get stuck for a few minutes during boot with
this message:

    Clear memory in MRC per MOR request Start, Please wait for some minutes...

This indicates that the firmware is busy overwriting (slowly) the RAM
contents. This is triggered by the `CONFIG_RESET_ATTACK_MITIGATION`
kernel option, enabled by default in Debian kernels, setting the
`MemoryOverwriteRequestControl`/`MemoryOverwriteRequestControlLock`
UEFI variables.

A request to drop the kernel option has been submitted upstream:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=970861

Further details about the UEFI variables and their behaviour in the
EDK2 TianoCore firmware here:

https://edk2.groups.io/g/discuss/topic/77180459#381



The memory cleaning process seems to be largely outside of the control
of the free firmware, so the suggested option is to avoid triggering
it from the OS kernel. The best way to do so is still unclear and
should be discussed in the above Debian bug. In the meantime, increase
the timeouts.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

lava/common-boot-tpl-reboot.yaml

   - boot:
       namespace: system
       timeout:
-        minutes: 5
+        minutes: 15 # Minnowboards can spend a long time clearing memory due to MRC requests
       method: {{boot_method}}
       commands: {{boot_commands}}
       transfer_overlay:

lava/common-boot-tpl.yaml

@@ -69,7 +69,7 @@ actions:
   - boot:
       namespace: flash
       timeout:
-        minutes: 10
+        minutes: 30 # Minnowboards can spend a long time clearing memory due to MRC requests
       method: {{boot_method}}
       commands: nfs
       prompts:
@@ -107,7 +107,7 @@ actions:
   - boot:
       namespace: system
       timeout:
-        minutes: 5
+        minutes: 15 # Minnowboards can spend a long time clearing memory due to MRC requests
       method: {{boot_method}}
       commands: {{boot_commands}}
       transfer_overlay:

lava/group-nfs-tpl.yaml

@@ -71,7 +71,7 @@ actions:
   - boot:
       namespace: nfsboot
       timeout:
-        minutes: 15
+        minutes: 30 # Minnowboards can spend a long time clearing memory due to MRC requests
       method: {{boot_method}}
       commands: nfs
       transfer_overlay: