platform: Use IOMEM_ERR_PTR for ioremap error returns

Replace ERR_PTR() with IOMEM_ERR_PTR() in stubbed ioremap functions to
maintain type consistency. The functions return void __iomem * pointers
and IOMEM_ERR_PTR() provides proper type casting to avoid sparse warnings.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Pei Xiao <[e-mail]>
Link: https://patch.msgid.link/3[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/platform_device.h

···
 devm_platform_get_and_ioremap_resource(struct platform_device *pdev,
 				unsigned int index, struct resource **res)
 {
-	return ERR_PTR(-EINVAL);
+	return IOMEM_ERR_PTR(-EINVAL);
 }
 
 
···
 devm_platform_ioremap_resource(struct platform_device *pdev,
 			       unsigned int index)
 {
-	return ERR_PTR(-EINVAL);
+	return IOMEM_ERR_PTR(-EINVAL);
 }
 
 static inline void __iomem *
 devm_platform_ioremap_resource_byname(struct platform_device *pdev,
 				      const char *name)
 {
-	return ERR_PTR(-EINVAL);
+	return IOMEM_ERR_PTR(-EINVAL);
 }
 
 #endif