qup_i2c: Remove Soc specific check while enabling CORE_ON_EN bit

Enabling of CORE_ON_EN bit in qup_i2c driver is not dependent on soc.
Same code will work for all. Hence remove the SOC specific part from the
function.

CRs-Fixed: 335884
Change-Id: I55054b0c17e1710c1d268322f1a78c42c94b3db8
Signed-off-by: Pankaj Kumar <pakuma@codeaurora.org>