draw: always call util_cpu_detect() in draw context creation.

draw: always call util_cpu_detect() in draw context creation.

Since disabling denorms in draw_vbo() we require the util_cpu_caps to be
initialized there. Hence add another util_cpu_detect() call in
draw_create_context() which should ensure this.
(There is another call in draw_get_option_use_llvm() which only gets called
with x86 (not x86_64) but calling it always there wouldn't help since it most
likely wouldn't get called when compiling without llvm, so leave it alone
there.)
This fixes https://bugs.freedesktop.org/show_bug.cgi?id=66806.
(Because util_cpu_caps wasn't initialized when first calling util_fpstate_get()
hence it returning zero, but it would later get initialized by rtasm translate
code hence when draw call returned it unmasked all exceptions by calling
util_fpstate_set(). This was happening only with DRAW_USE_LLVM=0 or not
compiling with llvm, otherwise the llvm init code was calling it on time too.)

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>