scsi: megaraid_mm: Fix incorrect function name in header

scsi: megaraid_mm: Fix incorrect function name in header

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/megaraid/megaraid_mm.c:505: warning: expecting prototype for mraid_mm_attch_buf(). Prototype was for mraid_mm_attach_buf() instead

Link: https://lore.kernel.org/r/20210303144631.3175331-2-lee.jones@linaro.org
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: megaraidlinux.pdl@broadcom.com
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>