powerpc: Remove in_kernel_text()

Last user of in_kernel_text() stopped using in with
commit 549e8152de80 ("powerpc: Make the 64-bit kernel as a
position-independent executable").

Generic function is_kernel_text() does the same.

So remote it.

Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/2a3a5b6f[e-mail]

arch/powerpc/include/asm/sections.h

···
 extern char end_virt_trampolines[];
 #endif
 
-static inline int in_kernel_text(unsigned long addr)
-{
-	if (addr >= (unsigned long)_stext && addr < (unsigned long)__init_end)
-		return 1;
-
-	return 0;
-}
-
 static inline unsigned long kernel_toc_addr(void)
 {
 	/* Defined by the linker, see vmlinux.lds.S */