Fix argument types in sincos

[fjebaker]

Fix #229

I would add tests for these changes, but I'm not really sure where in the test suite to add them.

[maleadt]

Thanks!

Tests would go in here:

Metal.jl/test/device/intrinsics.jl

Lines 103 to 124 in d6f958c

	@testset "math" begin
	a = ones(Float32,1)
	a .* Float32(3.14)
	bufferA = MtlArray{eltype(a),length(size(a)),Shared}(a)
	vecA = unsafe_wrap(Vector{Float32}, pointer(bufferA), 1)
	function intr_test(arr)
	idx = thread_position_in_grid_1d()
	arr[idx] = cos(arr[idx])
	return nothing
	end
	@metal intr_test(bufferA)
	synchronize()
	@test vecA ≈ cos.(a)
	function intr_test2(arr)
	idx = thread_position_in_grid_1d()
	arr[idx] = Metal.rsqrt(arr[idx])
	return nothing
	end
	@metal intr_test2(bufferA)
	end

[fjebaker]

Is this line needed?

Metal.jl/test/device/intrinsics.jl

Line 105 in d6f958c

a .* Float32(3.14)

[maleadt]

Is this line needed?

Metal.jl/test/device/intrinsics.jl

Line 105 in d6f958c

a .* Float32(3.14)

I don't think so. Probably doesn't hurt either?