x86: Move kernel boot function to arch/x86/lib/bootm.c

The boot_zimage() function is badly named it can also boot a raw kernel.
Rename it, and try to avoid pointers for memory addresses as it involves
lots of casting.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/include/asm/zimage.h b/arch/x86/include/asm/zimage.h
index 0f36662..8e7dd42 100644
--- a/arch/x86/include/asm/zimage.h
+++ b/arch/x86/include/asm/zimage.h
@@ -35,10 +35,8 @@
 unsigned install_e820_map(unsigned max_entries, struct e820entry *);
 
 struct boot_params *load_zimage(char *image, unsigned long kernel_size,
-				void **load_address);
+				ulong *load_addressp);
 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 		 unsigned long initrd_addr, unsigned long initrd_size);
 
-void boot_zimage(void *setup_base, void *load_address);
-
 #endif