NIOS2: irqflags: rename a redefined register name

NIOS2: irqflags: rename a redefined register name

Both arch/nios2/ and drivers/mmc/host/tmio_mmc.c define a macro
with the name "CTL_STATUS". Change the one in arch/nios2/ to be
"CTL_FSTATUS" (flags status) to eliminate the build warning.

In file included from ../drivers/mmc/host/tmio_mmc.c:22:
drivers/mmc/host/tmio_mmc.h:31: warning: "CTL_STATUS" redefined
   31 | #define CTL_STATUS 0x1c
arch/nios2/include/asm/registers.h:14: note: this is the location of the previous definition
   14 | #define CTL_STATUS      0

Fixes: 24cb9785b261 ("nios2: Nios2 registers")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>