quark_se: Correctly wait for ARC_READY flag while initializing ARC

The bitwise AND operator was being applied to the boolean expression
"!shared_data->flags" instead of the whole expression because a
parenthesis was lacking.

This bug has been found using Coccinelle using the following spatch,
after finding a similar bug somewhere else in the code base:

      @@
      expression E1;
      expression E2;
      @@

      - !E1 & E2
      + !(E1 & E2)

No other instance of this defect has been found with this spatch.

Change-Id: I6b9ca092f4015c80ddc83c31ce540a92e67cdb11
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>