ARM: OMAP: clean up some smatch warnings, fix some printk(KERN_ERR ...

Resolve the following warnings from smatch:

arch/arm/mach-omap2/gpmc.c:282 gpmc_cs_set_timings() info: why not propagate 'div' from gpmc_cs_calc_divider() instead of -1?
arch/arm/mach-omap2/serial.c:328 omap_serial_init_port() error: 'pdev' dereferencing possible ERR_PTR()
arch/arm/mach-omap2/timer.c:213 omap2_gp_clockevent_init() Error invalid range 4096 to -1
arch/arm/mach-omap2/gpio.c:63 omap2_gpio_dev_init() warn: possible memory leak of 'pdata'
arch/arm/mach-omap2/omap_hwmod.c:1478 _assert_hardreset() warn: assigning -22 to unsigned variable 'ret'
arch/arm/mach-omap2/omap_hwmod.c:1487 _assert_hardreset() warn: 4294963201 is more than 255 (max '(ret)' can be) so this is always the same.
arch/arm/mach-omap2/omap_hwmod.c:1545 _read_hardreset() warn: assigning -22 to unsigned variable 'ret'
arch/arm/mach-omap2/omap_hwmod.c:1554 _read_hardreset() warn: 4294963201 is more than 255 (max '(ret)' can be) so this is always the same.
arch/arm/mach-omap2/dpll3xxx.c:629 omap3_clkoutx2_recalc() error: we previously assumed 'pclk' could be null (see line 627)
arch/arm/mach-omap2/board-n8x0.c:422 n8x0_mmc_late_init() Error invalid range 14 to 13
arch/arm/mach-omap1/leds-h2p2-debug.c:71 h2p2_dbg_leds_event() error: potentially derefencing uninitialized 'fpga'.
arch/arm/plat-omap/mux.c:79 omap_cfg_reg() Error invalid range 4096 to -1

Thanks to Tony Lindgren <tony@atomide.com> for pointing out that BUG()
can be disabled.  The changes in the first version that removed the
subsequent return() after BUG() states have been dropped.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>