PCI: cadence: Use bitfield for *quirk_retrain_flag* instead of bool

No functional change. As we are intending to add additional 1-bit
members in struct j721e_pcie_data/struct cdns_pcie_rc, use bitfields
instead of bool since it takes less space. As discussed in [1],
the preference is to use bitfileds instead of bool inside structures.

[1] -> https://lore.kernel.org/linux-fsdevel/CA+55aFzKQ6Pj18TB8p4Yr0M4t+S+BsiHH=BJNmn=76-NcjTj-g@mail.gmail.com/Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20210811123336.31357-2-kishon@ti.comSigned-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

drivers/pci/controller/cadence/pci-j721e.c

@@ -66,7 +66,7 @@ enum j721e_pcie_mode {
 
 struct j721e_pcie_data {
 	enum j721e_pcie_mode	mode;
-	bool quirk_retrain_flag;
+	unsigned int		quirk_retrain_flag:1;
 };
 
 static inline u32 j721e_pcie_user_readl(struct j721e_pcie *pcie, u32 offset)

drivers/pci/controller/cadence/pcie-cadence.h

@@ -303,7 +303,7 @@ struct cdns_pcie_rc {
 	u32			vendor_id;
 	u32			device_id;
 	bool			avail_ib_bar[CDNS_PCIE_RP_MAX_IB];
-	bool                    quirk_retrain_flag;
+	unsigned int		quirk_retrain_flag:1;
 };
 
 /**