util/inteltool: drop OS-specific rdmsr/wrmsr prototypes

The previous commit (that was not touching inteltool.h)
marking internal functions as static is commit 6faccd1f00

Tested on: FreeBSD 13.0-CURRENT r355582

Change-Id: I4aba72f39b528fd70451a4656fd6c835ff766e49
Signed-off-by: Idwer Vollering <vidwer@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37767
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jacob Garber <jgarber1@ualberta.ca>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

util/inteltool/inteltool.h

@@ -380,8 +380,6 @@ typedef struct { uint32_t hi, lo; } msr_t;
 #define rdmsr freebsd_rdmsr
 #define wrmsr freebsd_wrmsr
 typedef struct { uint32_t hi, lo; } msr_t;
-msr_t freebsd_rdmsr(int addr);
-int freebsd_wrmsr(int addr, msr_t msr);
 #endif
 typedef struct { uint16_t addr; int size; char *name; } io_register_t;
 typedef struct {