spirv-headers: PV should be 1.5.4

As upstream hasn't actually tagged 1.5.5, we should
continue to use 1.5.4 until it does.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/recipes-graphics/spir/spirv-headers_1.5.5.bb b/meta/recipes-graphics/spir/spirv-headers_1.5.4.bb
similarity index 100%
rename from meta/recipes-graphics/spir/spirv-headers_1.5.5.bb
rename to meta/recipes-graphics/spir/spirv-headers_1.5.4.bb