powerpc: Fix comment in smu.h

Change 'Kenrel' to 'Kernel'
Signed-off-by: Yannick Guerrini <yguerrini@tomshardware.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

arch/powerpc/include/asm/smu.h

@@ -478,7 +478,7 @@ extern unsigned long smu_cmdbuf_abs;
 
 
 /*
- * Kenrel asynchronous i2c interface
+ * Kernel asynchronous i2c interface
  */
 
 #define SMU_I2C_READ_MAX	0x1d