ARC: unaligned: relax the check for gcc supporting -mno-unaligned-access

Without bleeding edge gcc, kernel builds were tripping everywhere.

So current gcc will generate unaligned code despite
!CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS but that is something we have to
live with.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/kernel/setup.c

@@ -314,18 +314,6 @@ static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
 		       IS_AVAIL1(cpu->extn_mpy.ver, mpy_opt),
 		       IS_AVAIL1(cpu->isa.div_rem, "div_rem "));
 
-
-#if defined(__ARC_UNALIGNED__) && !defined(CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS)
-	/*
-	 * gcc 7.3.1 (GNU 2018.03) onwards generate unaligned access by default
-	 * but -mno-unaligned-access to disable that didn't work until gcc 8.2.1
-	 * (GNU 2019.03). So landing here implies the interim period, when
-	 * despite Kconfig being off, gcc is generating unaligned accesses which
-	 * could bomb later on. So better to disallow such broken builds
-	 */
-	BUILD_BUG_ON_MSG(1, "gcc doesn't support -mno-unaligned-access");
-#endif
-
 	if (cpu->bpu.ver) {
 		n += scnprintf(buf + n, len - n,
 			      "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",