drivers/char/mxser.c: fix compilation warning in mxser.c

Both mxser_disable_must_enchance_mode() and mxser_get_must_hardware_id()
called from function CheckIsMoxaMust(), when CONFIG_PCI=y. So mark both
the functions under CONFIG_PCI.

We were warned by the following warning.

drivers/char/mxser.c:306: warning: `mxser_disable_must_enchance_mode' defined but not used
drivers/char/mxser.c:391: warning: `mxser_get_must_hardware_id'
defined but not used

Signed-off-by: Rakib Mullick <[e-mail]>
Cc: Jiri Slaby <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/mxser.c

···
 	outb(oldlcr, baseio + UART_LCR);
 }
 
+#ifdef	CONFIG_PCI
 static void mxser_disable_must_enchance_mode(unsigned long baseio)
 {
 	u8 oldlcr;
···
 	outb(efr, baseio + MOXA_MUST_EFR_REGISTER);
 	outb(oldlcr, baseio + UART_LCR);
 }
+#endif
 
 static void mxser_set_must_xon1_value(unsigned long baseio, u8 value)
 {
···
 	outb(oldlcr, baseio + UART_LCR);
 }
 
+#ifdef CONFIG_PCI
 static void mxser_get_must_hardware_id(unsigned long baseio, u8 *pId)
 {
 	u8 oldlcr;
···
 	*pId = inb(baseio + MOXA_MUST_HWID_REGISTER);
 	outb(oldlcr, baseio + UART_LCR);
 }
+#endif
 
 static void SET_MOXA_MUST_NO_SOFTWARE_FLOW_CONTROL(unsigned long baseio)
 {