Fix PR 22567: set SAL .section in minsym_found

Fix PR 22567: set SAL .section in minsym_found

PR 22567 is that breakpoint location can't correct gdbarch from SAL,
because its fields .section and .symtab is NULL.  We use to have code
setting .section, but was removed by 4024cf2

-  if (msymbol_is_text (msymbol))
+  CORE_ADDR func_addr;
+  if (msymbol_is_function (objfile, msymbol, &func_addr))
     {
-      sal = find_pc_sect_line (MSYMBOL_VALUE_ADDRESS (objfile, msymbol),
-                              (struct obj_section *) 0, 0);
-      sal.section = MSYMBOL_OBJ_SECTION (objfile, msymbol);

this patch adds this back by moving it to the common place at the bottom
of the function.

gdb:

2017-12-08  Yao Qi  <yao.qi@linaro.org>

	PR breakpionts/22567
	* linespec.c (minsym_found): Set sal.section.