scripts/spelling.txt: add regsiter -> register spelling mistake

This typo is quite common.  Fix it and add it to the spelling file so
that checkpatch catches it earlier.

Link: http://lkml.kernel.org/r/20170317011131.6881-2-sboyd@codeaurora.org
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/bcma/bcma_driver_pci.h b/include/linux/bcma/bcma_driver_pci.h
index 9657f11..bca6a5e 100644
--- a/include/linux/bcma/bcma_driver_pci.h
+++ b/include/linux/bcma/bcma_driver_pci.h
@@ -80,7 +80,7 @@ struct pci_dev;
 #define  BCMA_CORE_PCI_MDIODATA_DEV_TX		0x1e	/* SERDES TX Dev */
 #define  BCMA_CORE_PCI_MDIODATA_DEV_RX		0x1f	/* SERDES RX Dev */
 #define BCMA_CORE_PCI_PCIEIND_ADDR		0x0130	/* indirect access to the internal register */
-#define BCMA_CORE_PCI_PCIEIND_DATA		0x0134	/* Data to/from the internal regsiter */
+#define BCMA_CORE_PCI_PCIEIND_DATA		0x0134	/* Data to/from the internal register */
 #define BCMA_CORE_PCI_CLKREQENCTRL		0x0138	/*  >= rev 6, Clkreq rdma control */
 #define BCMA_CORE_PCI_PCICFG0			0x0400	/* PCI config space 0 (rev >= 8) */
 #define BCMA_CORE_PCI_PCICFG1			0x0500	/* PCI config space 1 (rev >= 8) */