r600/sb: Fix an &/&& mistake

r600/sb: Fix an &/&& mistake

gcc says:

    sb/sb_sched.cpp: In member function 'bool r600_sb::alu_group_tracker::try_reserve(r600_sb::alu_node*)':
    sb/sb_sched.cpp:492:7: warning: suggest parentheses around operand of '!' or change '&' to '&&' or '!' to '~' [-Wparentheses]
      if (!trans & fbs)

It happens to be harmless; if fbs is ever non-zero, it will be VEC_210,
which is 5, so (!trans & 5) == 1 and the branch works as expected.  But
logical AND is clearly what was meant.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>