LoongArch: Avoid uninitialized alignment_mask

The hardware monitoring points for instruction fetching and load/store
operations need to align 4 bytes and 1/2/4/8 bytes respectively.
Reported-by: Colin King <colin.i.king@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/kernel/hw_breakpoint.c

@@ -396,6 +396,8 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
 
 	if (hw->ctrl.type != LOONGARCH_BREAKPOINT_EXECUTE)
 		alignment_mask = 0x7;
+	else
+		alignment_mask = 0x3;
 	offset = hw->address & alignment_mask;
 
 	hw->address &= ~alignment_mask;