Remove vkGetInstanceProcAddr from exported symbols on Fuchsia

Fuchsia only allows access to the ICD's functions, through the Vulkan
Loader interface functions.

Exporting this function was copied from the android_vk_swiftshader.lds
file, but it has been removed from the latter due to causing direct
access to methods that should have an overridden implementation. Similar
issues are likely to occur on Fuchsia if we keep this function exported.

Bug: b/148822450
Change-Id: I12f2dad933abcd9dbf89518ac5714b9f936419e4
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/53609
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: David Turner <digit@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Vulkan/fuchsia_vk_swiftshader.lds b/src/Vulkan/fuchsia_vk_swiftshader.lds
index 919fceb..2237ffb 100644
--- a/src/Vulkan/fuchsia_vk_swiftshader.lds
+++ b/src/Vulkan/fuchsia_vk_swiftshader.lds
@@ -3,8 +3,6 @@
 # that is specific to the Fuchsia Vulkan loader implementation.
 {
 global:
-	vkGetInstanceProcAddr;
-
 	# Loader-ICD interface functions
 	vk_icdGetInstanceProcAddr;
 	vk_icdNegotiateLoaderICDInterfaceVersion;