i965/fs: Fix conversions float->bool, int->bool

i965/fs: Fix conversions float->bool, int->bool

Fixes gles2conform GL.equal.equal_bvec2_frag.

This fixes brw_fs_visitor's translation of ir_unop_f2b.  It used CMP to
convert the float to one of 0 or ~0. However, the convention in the
compiler is that true is represented by 1, not ~0. This patch adds an AND
to convert ~0 to 1.

By inspection, a similar problem existed with ir_unop_i2b, with a similar
fix.

[v2 kayden]: eliminate extra temporary register.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49621
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>