misc: rtsx: Fix symbol clashes

drivers/staging/rts5208/sd.o: In function `.sd_power_off_card3v3':
(.text+0x5760): multiple definition of `.sd_power_off_card3v3'
drivers/misc/cardreader/rtsx_pcr.o:(.text+0x4630): first defined here
drivers/staging/rts5208/sd.o:(.opd+0x378): multiple definition of `sd_power_off_card3v3'
drivers/misc/cardreader/rtsx_pcr.o:(.opd+0x4f8): first defined here
drivers/staging/rts5208/ms.o: In function `.ms_power_off_card3v3':
(.text+0x5e70): multiple definition of `.ms_power_off_card3v3'
drivers/misc/cardreader/rtsx_pcr.o:(.text+0x46e0): first defined here
drivers/staging/rts5208/ms.o:(.opd+0x360): multiple definition of `ms_power_off_card3v3'
drivers/misc/cardreader/rtsx_pcr.o:(.opd+0x510): first defined here

Fixes: 5da4e04a ("misc: rtsx: Add support for RTS5260")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Lee Jones <lee.jones@linaro.org>