Increased timeout to 15 mins for 'Is PNOR Flash Done'

Increased timeout to 15 mins for 'Is PNOR Flash Done' in 'Update PNOR Image'.

Change-Id: I106621d6199153815cd0c1c381f8ed0bbcdef5e4
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/extended/test_bios_update.robot b/extended/test_bios_update.robot
index a688043..607b6c6 100644
--- a/extended/test_bios_update.robot
+++ b/extended/test_bios_update.robot
@@ -58,7 +58,7 @@
     Run Key  Copy PNOR to BMC
     ${pnor_path}  ${pnor_basename}=  Split Path  ${PNOR_IMAGE_PATH}
     Run Key  Flash PNOR \ /tmp/${pnor_basename}
-    Run Key  Wait Until Keyword Succeeds \ 7 min \ 10 sec \ Is PNOR Flash Done
+    Run Key  Wait Until Keyword Succeeds \ 15 min \ 10 sec \ Is PNOR Flash Done
 
 Validate Power On
     [Documentation]  Power the host on, and validate that the system booted.