USB: fsl_qe_udc: Check for muram allocation errors

The QE UDC doesn't check for cpm_muram_alloc() return values, this
might cause all sorts of misbehaviour when cpm_muram_alloc() failed
to allocate the muram memory.

While at at, change few dev_dbg() calls to dev_err(), so that the
driver would not die silently.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>