Don't refer to x86-specific function on other architectures to avoid linker error.

Submitted upstream at <https://marc.info/?l=linux-bluetooth&m=160857625608440&w=2>

diff --git a/sbc/sbc_primitives.c b/sbc/sbc_primitives.c
--- a/sbc/sbc_primitives.c
+++ b/sbc/sbc_primitives.c
@@ -593,7 +593,9 @@ static int sbc_calc_scalefactors_j(
 
 static void sbc_init_primitives_x86(struct sbc_encoder_state *state)
 {
+#if defined(__x86_64__) || defined(__i386__)
 	__builtin_cpu_init();
+#endif
 
 #ifdef SBC_BUILD_WITH_MMX_SUPPORT
 	if (__builtin_cpu_supports("mmx"))
td class='form'><form method='get'>
<input type='hidden' name='id' value='3d871095f2aec355bc4ebea63e75f76dbc79a9be'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>refs</a><a class='active' href='/guix/log/gnu/services/dict.scm'>log</a><a href='/guix/tree/gnu/services/dict.scm?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>tree</a><a href='/guix/commit/gnu/services/dict.scm?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>commit</a><a href='/guix/diff/gnu/services/dict.scm?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/services/dict.scm'>
<input type='hidden' name='id' value='3d871095f2aec355bc4ebea63e75f76dbc79a9be'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>root</a>/<a href='/guix/log/gnu?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>gnu</a>/<a href='/guix/log/gnu/services?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>services</a>/<a href='/guix/log/gnu/services/dict.scm?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be'>dict.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/services/dict.scm?id=3d871095f2aec355bc4ebea63e75f76dbc79a9be&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>