e1000: Avoid unhandled IRQ
e1000: Avoid unhandled IRQ

If hardware asserted an interrupt and driver is down,
then there is nothing to do so return IRQ_HANDLED
instead of IRQ_NONE. Returning IRQ_NONE in above
situation causes screaming IRQ on virtual machines.

CC: Andy Gospodarek <235a7d7680e417ef53409d6a24f3311a70688752@redhat.com>
Signed-off-by: Tushar Dave <87283134ef8c4467e5607edc1225ad1197ffdd4c@intel.com>
Signed-off-by: Jesse Brandeburg <e6047e445db6578741afb14ef640164ef6b65e4f@intel.com>
Tested-by: <89ae28dca346dcf475c1c4c5ccad0a12c81be577@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs