spi: cadence-quadspi: fix potential malfunction after ~49 days uptime

The get_timer function returns an unsigned long which may be calculated
from the ARM system counter. This counter is reset only on a cold reset.
U-boot divides this counter down to a 1000 Hz counter that will cross
the 32bit barrier after a bit more than 49 days. Assigning the value to
an unsigned int will truncate it on 64bit systems.
Passing this truncated value back to the get_timer function will return
a very large value that is certainly larger than the timeout and so will
go down the error path and besides stopping U-Boot will lead to messages
like

    "SPI: QSPI is still busy after poll for 5000 ms."

Signed-off-by: Ronald Wahl <ronald.wahl@legrand.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index 93ab2b5..f2f69cf 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -151,9 +151,9 @@
 /* Return 1 if idle, otherwise return 0 (busy). */
 static unsigned int cadence_qspi_wait_idle(void *reg_base)
 {
-	unsigned int start, count = 0;
+	unsigned long start, count = 0;
 	/* timeout in unit of ms */
-	unsigned int timeout = 5000;
+	unsigned long timeout = 5000;
 
 	start = get_timer(0);
 	for ( ; get_timer(start) < timeout ; ) {
@@ -170,7 +170,7 @@
 	}
 
 	/* Timeout, still in busy mode. */
-	printf("QSPI: QSPI is still busy after poll for %d ms.\n", timeout);
+	printf("QSPI: QSPI is still busy after poll for %lu ms.\n", timeout);
 	return 0;
 }