OMAP2xxx clock: fix broken cpu_mask code

OMAP2xxx clock: fix broken cpu_mask code

Commit 8ad8ff6548f1c0bcbeaa02f274b3927c5015a921 breaks the OMAP2xxx
cpu_mask code, which causes OMAP2xxx to panic on boot.  Fix by
removing the cpu_mask auto variable and by changing CK_242X
and CK_243X to use RATE_IN_242X/RATE_IN_243X.

Resolves

<1>Unable to handle kernel NULL pointer dereference at virtual address 0000000c
<1>pgd = c0004000
<1>[0000000c] *pgd=00000000
Internal error: Oops: 5 [#1]
Modules linked in:
CPU: 0    Not tainted  (2.6.29-omap1 #32)
PC is at omap2_clk_set_parent+0x104/0x120
LR is at omap2_clk_set_parent+0x28/0x120

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Cc: Russell King <linux@arm.linux.org.uk>