dmaengine: INTEL_LDMA should depend on X86

The Intel Lightning Mountain (LGM) DMA controller is only present on
Intel Lightning Mountain SoCs.  Hence add a dependency on X86, to
prevent asking the user about this driver when configuring a kernel
without Intel Lightning Mountain platform support.

While at it, fix a misspelling of "Intel".

Fixes: 32d31c79

 ("dmaengine: Add Intel LGM SoC DMA support.")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210129131702.2656060-1-geert+renesas@glider.be


Signed-off-by: Vinod Koul <vkoul@kernel.org>