pata_of_platform: Remove "electra-ide" quirk

"electra-ide" is not used anywhere in the kernel and could be
represented in devicetree in a normal way.
This patch removes specific quirk for "electra-ide".

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Tejun Heo <tj@kernel.org>