mfd: lpc_sch: Rename GPIOBASE to prevent build error

mfd: lpc_sch: Rename GPIOBASE to prevent build error

One MIPS platform (mach-rc32434) defines GPIOBASE. This macro
conflicts with one of the same name in lpc_sch.c. Rename the latter one
to prevent the build error.

../drivers/mfd/lpc_sch.c:25: error: "GPIOBASE" redefined [-Werror]
   25 | #define GPIOBASE        0x44
../arch/mips/include/asm/mach-rc32434/rb.h:32: note: this is the location of the previous definition
   32 | #define GPIOBASE        0x050000

Cc: Denis Turischev <denis@compulab.co.il>
Fixes: ad1f88037b76 ("mfd: Introduce lpc_sch for Intel SCH LPC bridge")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>