usb: f_mass_storage: Fix set_bit and clear_bit usage

Compiling the f_mass_storage driver for an x86 target results in a
compilation error as set_bit and clear_bit are provided by bitops.h

Looking at the provenance of the current u-boot code and the git change
history in the kernel, it looks like we have a local copy of set_bit and
clear_bit as a hold-over from porting the Linux driver into u-boot.

These days __set_bit and __clear_bit are optionally provided by an arch and
can be used as inputs to generic_bit_set and generic_bit_clear.

This patch switches over to generic_set_bit and generic_clear_bit to
accommodate.

Tested on i.MX WaRP7 and Intel Edison

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Lukasz Majewski <lukma@denx.de>
Cc: Marek Vasut <marex@denx.de>

drivers/usb/gadget/f_mass_storage.c

@@ -251,6 +251,7 @@
 #include <usb_mass_storage.h>
 
 #include <asm/unaligned.h>
+#include <linux/bitops.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/composite.h>
@@ -282,26 +283,6 @@ static const char fsg_string_interface[] = "Mass Storage";
 struct kref {int x; };
 struct completion {int x; };
 
-inline void set_bit(int nr, volatile void *addr)
-{
-	int	mask;
-	unsigned int *a = (unsigned int *) addr;
-
-	a += nr >> 5;
-	mask = 1 << (nr & 0x1f);
-	*a |= mask;
-}
-
-inline void clear_bit(int nr, volatile void *addr)
-{
-	int	mask;
-	unsigned int *a = (unsigned int *) addr;
-
-	a += nr >> 5;
-	mask = 1 << (nr & 0x1f);
-	*a &= ~mask;
-}
-
 struct fsg_dev;
 struct fsg_common;
 
@@ -2085,7 +2066,7 @@ static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
 		 * we can simply accept and discard any data received
 		 * until the next reset. */
 		wedge_bulk_in_endpoint(fsg);
-		set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+		generic_set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
 		return -EINVAL;
 	}
 
@@ -2249,7 +2230,7 @@ reset:
 	fsg->bulk_out_enabled = 1;
 	common->bulk_out_maxpacket =
 				le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
-	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+	generic_clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
 
 	/* Allocate the requests */
 	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {