msm: emac: move clocks from driver to device

Clocks should be device specific to allow multiple devices.
Clock IDs and clock rates are changed to enumeration since
they are strongly related set of constants.

Change-Id: I20fc48c065a53dba89008ca204b422e95138165f
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>