parisc: PDT: Fix missing prototype warning

As reported by the kernel test robot, the following error occurs:

arch/parisc/kernel/pdt.c:65:6: warning: no previous prototype for 'arch_report_meminfo' [-Wmissing-prototypes]
65 | void arch_report_meminfo(struct seq_file *m)
| ^~~~~~~~~~~~~~~~~~~

arch_report_meminfo() is declared in include/linux/proc_fs.h and only
defined when CONFIG_PROC_FS is enabled. Wrap its definition in #ifdef
CONFIG_PROC_FS to fix the -Wmissing-prototypes warning.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Yu-Chun Lin <[e-mail]>
Signed-off-by: Helge Deller <[e-mail]>

arch/parisc/kernel/pdt.c

···
 #define PDT_ADDR_PERM_ERR	(pdt_type != PDT_PDC ? 2UL : 0UL)
 #define PDT_ADDR_SINGLE_ERR	1UL
 
+#ifdef CONFIG_PROC_FS
 /* report PDT entries via /proc/meminfo */
 void arch_report_meminfo(struct seq_file *m)
 {
···
 	seq_printf(m, "PDT_cur_entries: %7lu\n",
 			pdt_status.pdt_entries);
 }
+#endif
 
 static int get_info_pat_new(void)
 {