export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()

With the special case handling for Blackfin and Metag was removed by
commit 94e58e0ac3 ("export.h: remove code for prefixing symbols with
underscore"), VMLINUX_SYMBOL() is no-op.

Replace the remaining usages, then remove the definition of
VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

usr/initramfs_data.S

@@ -30,8 +30,8 @@ __irf_start:
 .incbin __stringify(INITRAMFS_IMAGE)
 __irf_end:
 .section .init.ramfs.info,"a"
-.globl VMLINUX_SYMBOL(__initramfs_size)
-VMLINUX_SYMBOL(__initramfs_size):
+.globl __initramfs_size
+__initramfs_size:
 #ifdef CONFIG_64BIT
 	.quad __irf_end - __irf_start
 #else